Astronomy & Space Exploration

rcoobc said:
I think if there is a lesson from both Apollo-13 and Colombia, it's that supplying the crew with additional power and carbon dioxide recyclers, is a good idea. Apollo 13 wouldn't have survived without getting the CO2 scrubbers working. Colombia could have if they had had extra.

Of course that is easier said than done when every kg of weight, you pay for 20 times over in fuel
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I thought Columbia disintegrated?
 
matherto said:
I thought Columbia disintegrated?
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Columbia did. But NASA knew of the problem whilst Columbia was in orbit. If Columbia had been fitted with more CO2 scrubbers, and more oxygen, the crew could have survived up in orbit for far longer, and NASA could have launched a rescue mission.

If every Columbia had been fitted with enough supplies for a 100 day journey, I imagine the crew would still be here today.

https://arstechnica.com/science/201...that-might-have-saved-space-shuttle-columbia/

And bringing 100 days worth of provisions isn't exactly a crazy idea, given that that's pretty much what they'd bring for an ISS mission, and on this mission the crew would have no lifeboat, unlike aboard the ISS
 
rcoobc said:
Columbia did. But NASA knew of the problem whilst Columbia was in orbit. If Columbia had been fitted with more CO2 scrubbers, and more oxygen, the crew could have survived up in orbit for far longer, and NASA could have launched a rescue mission.

If every Columbia had been fitted with enough supplies for a 100 day journey, I imagine the crew would still be here today.

https://arstechnica.com/science/201...that-might-have-saved-space-shuttle-columbia/

And bringing 100 days worth of provisions isn't exactly a crazy idea, given that that's pretty much what they'd bring for an ISS mission, and on this mission the crew would have no lifeboat, unlike aboard the ISS
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Ahhh cheers for the clarification.

I was only thinking about the actual reentry accident and knew that there was absolutely no way they could've survived.
 
Nikhil said:
Oh okay, I didn't know you were referring to their orbital planes. Yeah, moving from one orbit to another requires large amounts of fuel so going to the ISS which has an inclination of 51.6 degrees would be out of the question. The only thing that could have been done to bring back the crew would have been to send another shuttle up, maybe the Discovery.

It's still unfathomable that NASA gave the go ahead to the Space Shuttle programme when there were so many faults in terms of safety etc. Also the SS programme started in the early 80s and the Columbia disaster happened in 2003. But even after Challenger, they didn't develop in Launch Abort System for the shuttle?! I'm not sure about how useful those ejection seats were.

Edit: Wiki gives something about this. I'll just leave it here.

https://en.wikipedia.org/wiki/Space_Shuttle_abort_modes#Post-Challenger_abort_enhancements
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Ejection seats? At that speed during re-entry? It's either being fried to death by the friction generated heat, or being knocked out cold by the impact upon ejection.
 
Raoul said:
Thread meltdown in 3, 2, 1 ......

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Okay, first thoughts without readying beyond the headline.

If they can find a way to do it without further subsidizing the cost, then they should do it and do it ASAP.

If they can find a way to do it whilst keeping the science part active, then a small subsidization is okay.

Problems include;

- The ISS is an aging structure. At some point it would just be easier to deorbit it and put something better up there.
- The ISS is a giant laboratory. You could arguably put a 50 person hotel into LEO on a single Falcon Heavy launch (with Bigelow rooms attached), whereas the ISS would get cramped with just 10 people.

But yeah, the ISS is NASA's second biggest financial drain and commercializing it could be great.

Edit - should also say that space tourists have visited the ISS on multiple occasions already
 
rcoobc said:
Okay, first thoughts without readying beyond the headline.

If they can find a way to do it without further subsidizing the cost, then they should do it and do it ASAP.

If they can find a way to do it whilst keeping the science part active, then a small subsidization is okay.

Problems include;

- The ISS is an aging structure. At some point it would just be easier to deorbit it and put something better up there.
- The ISS is a giant laboratory. You could arguably put a 50 person hotel into LEO on a single Falcon Heavy launch (with Bigelow rooms attached), whereas the ISS would get cramped with just 10 people.

But yeah, the ISS is NASA's second biggest financial drain and commercializing it could be great.
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I definitely agree that we needs something a bit more modern up there, but don't think private funding is the way to go.
 
It seems a dumb idea. Commercial launch provision has worked out so far because a) they've had somewhere to go (the ISS) and b) NASA/the government have been the ones paying them. It worked out well for everyone involved. How does a private company benefit from this one? Supposing they can get the annual operating costs of the station down from $3-4bn to, say, $1bn (because "efficiencies"), that's still gonna take a hell of a lot of tourists/experiments to even get close to making it up or a few willing to pay absurd amounts (who can already go up there if they want to). And the only way a lot of people could afford the launch cost would be if BFR is flying, and if BFR is flying you're already in orbit aboard a spaceship that has plenty of internal volume and the ability to land on the Moon.

This is supposedly for 2025 and after, which is only a few years short of its current planned retirement in 2028. Just fund it to completion and let it die the meteoric plasma-death that it's earned.
 
I find the idea of the ISS orbiting the Moon instead of having it in LEO very appealing. The costs of launching payloads and getting personnel up there would be massive though. Not to mention how useful that would actually be as the ISS astronauts conduct various experiments up there that may be atmosphere or Earth related.
 
Raoul said:
I definitely agree that we needs something a bit more modern up there, but don't think private funding is the way to go.
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What we need is a Space Port.

Everything hinges on the BFR. It's a complete game changer if it works as Elon says it will, everything changes. We have a future like out of all our favourite science fiction.

Marcus Freeman took his seat on the Express BFR Mk III. He looked around, most of the other passengers had the nervous grimace of virgin space tourists. Men and women of all sorts of nationalities, laughing and joking with each other in every language, all muffled by the flight suits they all wore. Most of the suits were plain white, emblazoned with the SpaceX logo, although a few had various insignia's from sponsoring countries and organisations. In truth he wasn't much of a space veteran, having only been to space once before on the Voyager BFR Mk II, but it was an extended stay of around 55 days, and involved a trip down to the moon.

"What class are you going to be in when we reach the Space Port Freedom?"

A woman sitting nearby had noticed him looking around, and struck up conversation.

"Oh, I'm not actually staying at Port, I'm assisting in the installation of M.O.P.2 down on Alpha." Marcus replied. That was the other reason he wasn't feeling nervous, the company had given him extensive training for this, unlike the one month "how not to die" training that the tourists got.

"Does that mean you get to go for free?!" The woman asked. She was pretty looking. Asian, probably Korean, but with no noticeable accent that Marcus could discern, so he assumed she was American. "I can't believe how much I've spent on this," she continued, "my husband nearly killed me, but it's Space, you know. I've been dreaming about this since I was a child. Probably even earlier than that."

"You've been dreaming about this before you were a child?" Marcus laughed. She was clearly nervous. "Yes, I get to go for free. This is actually my second trip to space and the second time I will have been down to the lunar surface. So I should say thank you to you and your husband, as you're paying for my trip!" A bit too arrogant there. He was going for jokey, but he wasn't quite sure he'd hit the mark. He decided to try sympathy next. "Don't worry, these things are unbelievably safe now. The Mark III BFR should be officially safe enough for children to fly on within the next 5 years, except for under 12's due to the G Forces produced during descent."

She smiled. "Well if they can get the cost down further, maybe we can have a family vacation next time".

Just then a chiming music began playing and the passenger section lit up blue. "Time to buckle up" Marcus said, smiling at the woman again. Not that he had much chance with her if she had a husband, although who knows what she was going into space to experience. The 500 mile high club was a big draw for tourists.

The slightly ironically named flight attendants were coming round, checking to see that everyone was buckled in correctly, and that everyone's flight suit was active. SpaceX had clearly tried to make the initial checks feel as close to an airlines as possible, but unlike an air flight, the attendants wouldn't be coming too. The BFR had no attendants and no pilots, everything was computer controlled.

10 minutes later, and the countdown had been locked in. On the giant screen at the head of the passenger section, it showed a livestream of the Enterprise BFR sitting proud on it's booster, and blue skies smiling down. There had been some worry that high winds would stop the launch, and the 155 passengers would have to disembark and try again the next day. But thankfully the winds had settled down.

"How long are you staying for?" Marcus asked the woman. "Just 2 weeks," she replied back. It was harder to talk now, the flight suits had taken over the supply of air to the passengers, making talking normally almost impossible. Instead, you could choose to talk to anyone on the ship (or telephone anyone off it) using the controls on the arm rest, the sound being piped in through speakers. Marcus had chosen to keep talking to the woman. "How long are you staying for?" she asked him back. "Are you staying on Freedom before going down to the moon?"

"Yes, I have a three day stay at Port Freedom before the Vanguard Translunar Ship will be ready to return to Lunar orbit. It will actually be at the Port when we arrive, but it's refuelling one of the Hermes tankers, and having cargo removed.

"How much cargo could be on the Vanguard, I thought it was just a tanker?" Marcus was surprised she knew that. "It is, but there are 5 seats for crew as well, and a small hold for cargo." The woman smiled. "Well if you are at the port for a couple days and have some free time, come find me!" She was definitely flirting with him. "Thanks but you'll be throwing up for the first few days. I'd rather miss that!" Smooth, idiot. "I promise I'll recover quickly, come find me Mr Freeman". She'd read his last name from the seating chart on the arm rest that let them communicate with each other. He realised he hadn't asked for her first name. He'd also not been paying attention to launch clock which read less than 30 seconds.

"Okay I will come find you if your husband doesn't mind! And I'm sorry, I haven't asked for your name."

"No you still haven't. It's Emily. And Ex-husband."

Just then, the engines kicked off with a roar, and it got far too loud to talk.
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Some things I think people don't think of with regards to the BFR and it's potential.

The Moon will be industrial and awesome

It optimally takes about 9-10 km/s delta v to get into Low Earth Orbit, 1.5-2 km/s of which is due to atmospheric drag. All that work that the BFR does with it's two stages are to get those hundred people into Low Earth Orbit, and the BFR can go no further.

Elon's suggestion is to refuel the BFR in LEO using 3 to 5 further BFR ships all launching from Earth. This is crazily inefficient compared to refuelling from the moon. Imagine instead a slightly larger BFR Tanker that;

- Refuels from the lunar surface
- Accelerates to translunar/transearth velocity (approx 2.74 km/s)
- Aerobrakes, and slips into LEO (little delta v needed).
- Refuels the BFR in LEO
- Accelerates back to the Moon and lands (approx 5.93 km/s needed, but is much lighter now).

You can do it slightly more efficiently with a two stage vehicle, but it's not necessary.
- A two stage ship, refuels on the Moon.
- The first stage accelerates both sections to translunar/transearth velocity (approx 2.74 km/s). The two stages then separate.
- The first stage free returns back to the moon landing back at the fuel depot (approx 2 km/s, but is now a lot lighter)
- The second stage decelerates using earth's atmosphere and slips into LEO (little Delta V)
- It refuels the BFR in LEO, then accelerates back to land on the Lunar Surface (approx 5.93 km/s, but has delivered most of it's fuel). If necessary, it can slip into LEO for about 4 km's and then refuel to get back to the lunar surface.

The first stage requires about 5 km/s of delta v, but 2.74 km/s of that is carrying nearly all the mass for both stages. The second stage requires more like 6 km/s delta v but carrying nearly low mass.
At first glance it doesn't seem like it saves much. 9 km/s to from moon -> LEO -> moon and 10 km/s from earth -> LEO -> earth

But there are two important differences. First, the moon has no atmosphere, so if you want to build the ship slightly bigger, you can. In fact, you have to deal with far less aerodynamic forces (only the aerobraking used to slow you down) so you can build it any shape or size you want. Second, when starting from earth, you deliver the payload after burning the 10 km/s. From the moon, you deliver the payload after only 2.74 km/s and return with no payload.

The refuelled BFR still won't have a full tank, but it should have enough to reach Low Lunar Orbit, requiring 4 km/s delta v. If you need slightly more delta v, you can refill the tanker in Low Lunar Orbit at the start, and/or finish in Low Lunar Orbit

So rather than requiring 6 BFR launches to get the Mars, you should be able to do it in one BFR Launch from Earth, one BFR launch from the moon, then a refill from lunar orbit.
 
rcoobc said:
Some things I think people don't think of with regards to the BFR and it's potential.

The Moon will be industrial and awesome

It optimally takes about 9-10 km/s delta v to get into Low Earth Orbit, 1.5-2 km/s of which is due to atmospheric drag. All that work that the BFR does with it's two stages are to get those hundred people into Low Earth Orbit, and the BFR can go no further.

Elon's suggestion is to refuel the BFR in LEO using 3 to 5 further BFR ships all launching from Earth. This is crazily inefficient compared to refuelling from the moon. Imagine instead a slightly larger BFR Tanker that;

- Refuels from the lunar surface
- Accelerates to translunar/transearth velocity (approx 2.74 km/s)
- Aerobrakes, and slips into LEO (little delta v needed).
- Refuels the BFR in LEO
- Accelerates back to the Moon and lands (approx 5.93 km/s needed, but is much lighter now).

You can do it slightly more efficiently with a two stage vehicle, but it's not necessary.
- A two stage ship, refuels on the Moon.
- The first stage accelerates both sections to translunar/transearth velocity (approx 2.74 km/s). The two stages then separate.
- The first stage free returns back to the moon landing back at the fuel depot (approx 2 km/s, but is now a lot lighter)
- The second stage decelerates using earth's atmosphere and slips into LEO (little Delta V)
- It refuels the BFR in LEO, then accelerates back to land on the Lunar Surface (approx 5.93 km/s, but has delivered most of it's fuel). If necessary, it can slip into LEO for about 4 km's and then refuel to get back to the lunar surface.

The first stage requires about 5 km/s of delta v, but 2.74 km/s of that is carrying nearly all the mass for both stages. The second stage requires more like 6 km/s delta v but carrying nearly low mass.
At first glance it doesn't seem like it saves much. 9 km/s to from moon -> LEO -> moon and 10 km/s from earth -> LEO -> earth

But there are two important differences. First, the moon has no atmosphere, so if you want to build the ship slightly bigger, you can. In fact, you have to deal with far less aerodynamic forces (only the aerobraking used to slow you down) so you can build it any shape or size you want. Second, when starting from earth, you deliver the payload after burning the 10 km/s. From the moon, you deliver the payload after only 2.74 km/s and return with no payload.

The refuelled BFR still won't have a full tank, but it should have enough to reach Low Lunar Orbit, requiring 4 km/s delta v. If you need slightly more delta v, you can refill the tanker in Low Lunar Orbit at the start, and/or finish in Low Lunar Orbit

So rather than requiring 6 BFR launches to get the Mars, you should be able to do it in one BFR Launch from Earth, one BFR launch from the moon, then a refill from lunar orbit.
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You'd still have to get a lot of methane to the lunar surface for it to be used as a fueling post, though.
 
Ubik said:
You'd still have to get a lot of methane to the lunar surface for it to be used as a fueling post, though.
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Yeah that's a bit of a problem. Not quite as easy to make methane on the moon as it is to make it on mars.

But you can easily make hydrogen and oxygen. In the future, it may be that a much larger ship goes from Mars -> HEO/Moon -> Mars using electric propulsion. - Hermes style.
 
rcoobc said:
Yeah that's a bit of a problem. Not quite as easy to make methane on the moon as it is to make it on mars.

But you can easily make hydrogen and oxygen. In the future, it may be that a much larger ship goes from Mars -> HEO/Moon -> Mars using electric propulsion. - Hermes style.
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Think Blue Origin will be the ones to watch regarding the Moon, who knows what New Armstrong will be like but if their nomenclature continues its trend it'll be targeting the Moon (Bezos has also said that they want to get there), and they've been developing hydrogen engines for 5+ years. BFR/S should beat them to landing there if it works out, but it's designed for Mars. If New Armstrong was similarly sized but had a more traditional (but still reusable) second stage, it would be like having a cheap version of Saturn V.
 
The true cost of space travel will only truely start plummeting when we are manufacturing on the moon. There is little gravity so you can build huge structures and easily move them about, there is no atmosphere so you can easily get them into orbit, and when sending things back to LEO you can use the earth's atmosphere to drop your apogee meaning it requires ridiculously little fuel. That's what I'm excited for.

Building a Star Trek sized ship would be basically impossible on earth, but dead simple relatively on the moon.

Hollow out a kilometre long creater. Put a roof on it and fill it with air. Build the star ship in a relatively earth like environment, then pump the air out and retract the roof.

Also, apparently the BFR has more energy than the bomb dropped on Hiroshima. So I really don't see how point to point earth travel will ever be possible on it
 
Expected lifespan of the roadster is in the order of 10s of millions of years

https://arxiv.org/pdf/1802.04718.pdf

Using an ensemble of several hundred realizations we were able to statistically determine the probability of the Tesla colliding with the solar system planets on astronomical timescales. Although some of the orbits experience resonant and secular effects, the orbital evolution remains dominated by close encounters with the terrestrial planets, in particular Earth, Venus and Mars. Most of our 3 Myr realizations do not result in collisions with any solar system bodies, but we do find many cases where the Tesla impacts the terrestrial planets. Specifically, we numerically calculate a collision probability of ≈ 6% and ≈ 2.5% with the Earth and Venus over one million years, respectively. This leads us to estimate the dynamical half-life of the Tesla to be a few tens of Myr, similar to other NEAs (Gladman et al. 1997).
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If we want to go get the roadster, first close approach with Earth is in 2091. Hopefully by then we can launch a space cafe to park it on
 
Been doing a bit of reading.

It would be much better to go to Titan, Europa and Enceladus than Mars.

Europa is one vast single ocean of water underneath a thick crust of ice on the surface. Titan is a lot like the earth and is the only other planet or moon in the Solar System to have stable liquid bodies on the surface.

NASA should put their full effort into sending that submarine to explore Titan's oceans and even a probe to explore it's surface. Also Europa, which has more water than all the oceans on Earth combined. They'll have to get past the surface though.

SpaceX can do all the Mars stuff.
 
Raoul said:
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Nikhil said:
Been doing a bit of reading.

It would be much better to go to Titan, Europa and Enceladus than Mars.

Europa is one vast single ocean of water underneath a thick crust of ice on the surface. Titan is a lot like the earth and is the only other planet or moon in the Solar System to have stable liquid bodies on the surface.

NASA should put their full effort into sending that submarine to explore Titan's oceans and even a probe to explore it's surface. Also Europa, which has more water than all the oceans on Earth combined. They'll have to get past the surface though.

SpaceX can do all the Mars stuff.
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This is why we need to go to Enceladus.
 
Some images captured from the Mars Rover courtesy of r/space in this gallery:

 
Check this out if youve never seen it before. Part of googles experiment department. Build on webgl and three.js I believe.

100000 Stars

Look at it on a pc.
 
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Maradona10 said:
Existential crisis in 3...2...1....

Its beautiful yet so haunting.
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When you zoom out you can click on the named stars and it shows you the wikipedia entry for that particular star. Pretty amazing project.

What really blows me away is to think that the sun is travelling at 828,000 km/h through the milky way. The entire galaxy is spinning faster than a fidget spinner!
 
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