Some thoughts from Dennis Wingo.
I haven’t crunched any numbers (and am unlikely to absent a paying client), but it struck me at the time that it was very unlikely that this mission is technically feasible in a single launch, unless the launcher is SLS. Which would, of course, put it outside the range of financial feasibility, not to mention schedule feasibility…
That’s actually a feature, though, rather than a bug. Demonstrating that a two-launch Mars scenario can work will dissipate much of the Fear, Uncertainty and Doubt promulgated by Senate Launch System boosters.
He raises a very good point on the trajectory. I’ve been wondering of a lunar grav assist would help, and that 475 day mission that includes a Venus flyby is one I’ve mentioned here before.
He’s got a very interesting point about the inflatable: it won’t have much storage capacity for launch. My guess has been that they’d use a solid module as a connecting trunk, but that seems precluded by the graphics they;ve shown, plus the mission paper. I was wondering if they could shoehorn it all into the Dragon just for launch and then move it. Also, is the avilible space in an inflatable at launch zero, or might there be some?
The lunar flyby is especially intriguing. Reducing the delta/v needed by 25% reduces the size of the TMI stage by a lot more – and that might make the single launch possible.
As for Fear, Uncertainty, and Doubt, I think SLS is using them for oxidizer, seeing as how it’s totally dependent upon them. 🙂
A venus flyby first means longer to mars risking putting that issue behind us.
We should definitely use a moon gravity assist.
Using more than one launch increases the cost putting the whole thing in jeopardy.
It’s always good to examine different ideas, but we need to be careful it doesn’t distract and interfere with the one good idea. Keep in mind the launch date was chosen to keep the costs doable.
In the future, a 100mt ship (40mt dry, 60mt crew and supplies) makes sense. But not for this.
A Venus flyby actually means less time to Mars and less mission time, as well as lower Earth departure delta/v. It’s a total mission time of 475 days vs. 501.
So, shorter total mission time, plus lower launch mass due to reduced delta/v needs.
The bad news; it’s a rare alignment, and it comes up quite a few months before the current launch window.
🙂
That’s round trip CJ. I was talking about the purpose of the trip, Mars Inspiration. We aren’t going to colonize venus for quite a while. Even with blimps.
I was just thinking that a total mission time of 475 days is better than 501 days, especially when the 475 days gets you two planetary flybys plus a lower TMI delta/v. saving 16 days from the total flight time might not be that big a deal, but the 25% reduction in needed TMI delta/v is.
I don’t see why we can’t colonize Venus, and do so soon. The heat isn’t a problem if we do this right. Politicians are always going to hot, sunny places on “fact finding” excursions (there seem to be a plethora of facts to be found on tropical beaches, for some reason). So, politicians like warm, exotic climates. Venus has a warm, exotic climate. Therefor, the answer is simple; we send politicians to colonize Venus, and the surface heat becomes a feature, not a bug.
🙂
Politicians to venus? I think you’re on to something. Actually, I think they tried that by telling people venus was populated with woman in the fifties. They didn’t take the bait then so I don’t think exotic climate thing would work either. But it certainly is worth working on. So folks, how do we entice the politicians?
My idea is two Dragons on either end of a BEAM. The BEAM and two Dragons come up on two seperate Falcon 9 V1.1’s, the BEAM riding in the trunk of one of them.
The second Dragon is packed with cargo to the point you can barely open the hatch. You would empty the cargo from that one into the torus of the BEAM.
The second Dragon would contain a treadmill and a toilet. The second Dragon could be configured to be used as a lifeboat by transferring the seats from Dragon 1.
Use an Atlas Centaur 551 or 552 to launch a Centaur with a low-boiloff drop tank as proposed for the early stages of the Golden Spike program. Any synergies with the GS people should be sought whenever possible as long as it does not jepordize the schedule as a cost-saving measure.
This way, you can assemble and check-out the craft in LEO before launching the kick-stage and commiting to TMI.
You could also use part of the tunnel of the BEAM for cargo, just transfer it first to the torus upon inflation.
Definitely.
Howinthehell did you manage to get a one-word response through the filters?
Magic.
It’s the peroid isn’t it?
i got my hands slapped by Titus the last time I broke the magicians code. But yes, it’s very close to the P-Roid.
Yup.
Tito is not out to stop SLS, he’s out to gain support for the “program of record,” including SLS as he made clear at the press conference. This has been reinforced to me by another person.
That doesn’t mean we can’t support the effort because of all the other good things it could do. I know that hard-core New Space guys were involved in helping with the ‘launch’ to the public. Now, they may disagree with Tito about SLS and “POR”, but they find the project so inspirational and potentially useful in showing off private energies at work that that they can agree to disagree on those points.
Tito is not out to stop SLS, he’s out to gain support for the “program of record,” including SLS as he made clear at the press conference.
That’s bad news. I find it very hard to understand his support for SLS / Orion. Two billion a year is being wasted on that, when it could have been used to launch propellant and thus create a large market for launch services. The combined effect of that and commercial crew on private spaceflight would be enormous.
It’s just as hard for me to understand, but it’s there and it’s not changing. So I believe we need to work from there with the positive impacts of his project while making clear where we disagree with his objectives, in context.
Sure, I didn’t mean to argue against this initiative or anyone who supports it. But do you think that if the propellant-launch-market-as-funding-for-RLVs argument were explained to him he’d still be in favour of SLS / Orion? Maybe he would, but it might be worth a try, if there’s anyone who supports the argument and has Tito’s ear.
I know it’s not something engineers tend to do, but could it be Tito is just playing politics concerning SLS? He’s not stupid. What does it hurt to praise an existing program supported by the guys that may decide the fate of his mission?
Totally unrelated to Inspiration Mars but I wanted to share this video on an inflatable concrete structure. This would seem to me to have definite possibilities on the Moon:
http://www.wimp.com/concretetent/
I recall that a key reason given by NASA for rejecting the original t/Space COTS bid was we proposed to employ two launches and orbital rendezvous as the way to boost cargo transferred to ISS while still keeping the flexibility and safety advantages of a smaller air-launched LV. NASA JSC said that was too risky…this while they were baselining the two mission return to the moon using both an Ares I and V. So risk is a very flexible requirement that is easily altered by whim.
But I agree a dual launch FH, (with two Dragons and a pair of nearly identical pressurized trunks) is the obvious right way to go.
But I agree a dual launch FH, (with two Dragons and a pair of nearly identical pressurized trunks) is the obvious right way to go.
It would be more obvious if FH had already flown and if the approach didn’t depend on an immutable launch window in the near future.
“As for Fear, Uncertainty, and Doubt, I think SLS is using them for oxidizer, seeing as how it’s totally dependent upon them.”
Actually, that is incorrect. Most mission scenarios, especially where Mars is concerned, call for more than one launch of the SLS, at least until a fuel factory is set up on the moon.
The quote in the above should have been: “That’s actually a feature, though, rather than a bug. Demonstrating that a two-launch Mars scenario can work will dissipate much of the Fear, Uncertainty and Doubt promulgated by Senate Launch System boosters.”
Rand
Absolutely. A two planet flyby with a two launches for the system offers some darned interesting eye candy and to be the first two humans to put eyeballs on both planets in one mission would be historic indeed. If the Moon was added as a third flyby, that would turn some heads.
I have my own idea about the flight system that I may be publishing this coming week. There are some very interesting trajectory options out there that I did not go into in my missive there.
The bottom line is that this is doable, not in a single launch but even two launches will shake the status quo to the foundations, whether Tito intends to or not.
Not that I disagree, but if trying to do that means not doing anything at all because of costs… then I’ve got to be against the idea. I am however, eager to hear the other trajectory thoughts.
Dennis,
Yes, in a single mission they would become the humans who traveled furthest from the Earth, the closest to the Sun and the furthest from the Sun.
BTW have you looked at the hardware Excalibur Almaz has available? They have two Alamz modules (Salyut 5) they are modifying for deep space use based on a plan that Russian was considering for one of its Mars missions. Although they are focus placing them in lunar orbit they could easily be used for a deep space mission like this one.
http://www.excaliburalmaz.com/0201_Lunar.html
I discount E-A as a viable system for long duration spaceflight.
There are 3 Falcon Heavy flights on the public Space X launch manifest, which runs to 2017. I wonder how many successful flights Tito would want to see before committing to put people on one.
If you can deliver a fully fueled Centaur, I think you can get away from having to use Falcon Heavy at all. My plan would use two F9’s and a Atlas 551 or 2 with a cyrogenic drop tank to recharge the second stage as the payload.
A near fully-fueled Centaur should have a much better TMI mass than the Kero upper of the FH.
The F9H LEO numbers are impressive. However, the C3 numbers are much closer between the F9 and the DIVH due to the LOX/H2 RL-10’s
Why not have FH deliver a Centaur to LEO with as much fuel as possible? That should be the easiest way.
BTW, what is the mass of a fully fueled Cebtaur stage?
According to Astronautix, the Centaur V1 specs are:
Gross mass: 22,825 kg (50,320 lb).
Unfuelled mass: 2,026 kg (4,466 lb).
Height: 12.68 m (41.60 ft).
Diameter: 3.05 m (10.00 ft).
Span: 3.05 m (10.00 ft).
Thrust: 99.19 kN (22,300 lbf).
Specific impulse: 451 s.
Burn time: 894 s.
That’s well inside the capacity of a Falcon Heavy. It shouldn’t be difficult to develop an extended tank version of the Centaur to allow for a longer burn time and a longer time. I’d also consider adding extra insulation to allow for longer on-orbit time before firing the engine(s).
If Falcon Heavy delivers it you have integration and fueling issues. I suspect the cryogenic drop tank that was discussed in the Golden Spike briefing would be cheaper to develop. I get the impression Musk wants to avoid hydrogen fro the foreseeable future.
Just let the Atlas do the work if it can.
Just one point I think might have been missed; the possible events of 2014 might make this whole discussion moot. If Mars does indeed get hit by 500 teratons or thereabouts in 2014, it might be a very unhealthy place indeed to visit for a while, what with the billions of tons of dust and the huge number of fragments in low orbit.
In such an event, it might also be necessary to take account of increased atmospheric density.
It’s not just about getting to orbital speed, but orbital velocity. Most debris will either fall back on mars or head out to orbit the sun. They’d have three years to check it out. 500 teratons sure sounds like a lot, but I don’t expect mars will get a third moon or ring because of it. What debris does make it to orbit only matters if the relative velocities with respect to a vehicle are high. Orbital mechanics mitigates that quite a bit.
Ken,
It really depends on the angle of impact. A shallow angle impact on the day side will probably put a lot more debris into orbit than a high angle impact will.
But the big problem will be not knowing what the actually debris situation is since the current armada of spacecraft in Mars orbit will likely be scrap metal and it will take a while for replacements to make it there to size it up.
Yes, the Hubble might be used to estimate it, but it would have its limited and the 100 mile high keystone the mission must pass through leaves little room for avoiding any debris cloud around it.
On the other hand, a terraform Mars will likely have government racing to reach it which would make a moot point of Dennis Tito’s mission anyway.
I don’t think the angle of impact matters much at all. You will note that craters are round, not oval. It’s basically a point of explosion, not billiard balls. If the two bodies were nearly the same size, that would be different.
To go into orbit, the debris has to follow a very specific path with an error much less than a degree. That velocity is much more horizontal to the surface than vertical. Even assuming some of the debris leaves the impact horizontally, that is still mostly vertical with regard to the entire planet.
The thing that changes all of the above is atmosphere, but mars clears dust in the atmosphere on a regular basis.
Our spacecraft orbiting mars may not even be in position to become scrap. Nor those on the surface (unless they are very unlucky.) Think about it, what’s the biggest crater on mars?
Laura Dern would probably be heading for the impact site with Dorothy 3.
Let’s hope it doesn’t get the interest of government!!!
Darn if it doesn’t hit.
Keeping it simple and focused.