Mar12
That’s what this professor from my alma mater thinks it will take to do a mission to Mars.
I obviously disagree, not that I’m that big a fan of Mars missions. I’m always disappointed at whom the press thinks is an expert on space policy. At least he’s an engineering professor, and not a “scientist.”
I’ll admit not clicking the link, because this is no longer relevant anyway. When I worked on a vehicle sizing study in the late 90′s for the “Mars Reference Mission”, we came up with a Star Trek size vessel to have adequate redendency of components and it’s equivalent mass. If the Professor was using the results of that study, he may be correct.
But, that mission was for landing and staying on Mars for over a year at a time. It including producing fuel on the planet. And it was based on technology available at the turn of the century. The whole point of the study was to determine what long term investments should be made in technology to make an impact in shrinking the size of the vessel. Over a decade later, some of those investments have paid off, and I think today, the vehicle size would be much smaller for that reference mission. The reference mission was also limited in essentially performing an Apollo style program with very slight modifications (like insitu fuel production).
He may also be trying to achieve a fast trip. As I understand, it requires a lot more delta v to cut travel time below six or seven months. Several varieties of nuclear and nuclear-powered propulsion are claimed to be able to cut that travel time to as low as three months.
This is actually one of the encouraging things about the future because fuel cost does dominate and fuel cost has the most potential for coming down. LOX from the moon having huge potential.
Orbital mechanics has a lot to do with costs. Until you look at a specific mission, it’s hard to nail down the actual costs.
I’m for sending more people and less mass (internal volume doesn’t have to require so much mass and provides a more comfortable journey.) My ref mission assumes two 40,000 kg ships each with 60,000 kg of 24 crew and supplies, and 500,000 kg of fuel/oxygen.
That’s more than 20 FH right there and it’s because of the fuel requirement.
It will take twenty to forty Saturn Vs to ensure lifetime gainful employment for the graduates of Michigan Engineering.
It could take that many, depending on the size of the mission.
Since he’s trying to get funding for a plasmadynamic thruster, he’s obviously chosen a mission size that’s sufficiently large to justify his development.
When listening to an “expert,” context is everything.
If they go with an Orion then I think 20 to 40 Saturn-V’s is a gross underestimate, since it takes a 684-foot, 25,000-ton amphibious transport dock with a crew of 800 or more just to recover the capsule at the end of the mission.
Orion recovery link at NASAspaceflight.com
I wonder if SpaceX will lease an entire Carnival Cruise liner to recover the Dragon after the next ISS delivery? Wait. I don’t wonder that at all. They’re not a government operation.
IIRC, SpaceX uses an ocean-going barge to recover their Dragon capsules. Having to pay your own expenses makes a big difference. NASA spent more on the launch tower for Ares (over $500 million) than SpaceX spend developing the Falcon 1 and Falcon 9. When you really want to spend big bucks, no one does it like the government.
Not to mention not having to worry about the Russians grabbing it first
I can’t watch the video right now so perhaps these questions were answered already:
1. What sort of mission profile does he use for his assumptions? For example, is he proposing “Direct Ascent” where everything needed for the return trip is landed on the Martian surface? Or perhaps a variation of the Apollo-style LOR with Mars Orbit Rendezvous?
2. Does he expect to boost all of the supplies needed for the entire mission from Earth orbit at the same time or send some parts ahead of the manned portion? It takes propellant to accelerate propellant. If you boost everything at the same time, it’ll likely require considerably more propellant.
3. Did he allow for any of the interesting ideas like those discussed yesterday of a lunar and/or Venus fly-by?
4. Does he allow for indigenous propellant production on the Martian surface? That could greatly reduce the mission requirements.
It’d be easy to come up with a brute force Mars mission architecture that would require at least as many Saturn V equivalent boosters as he suggests. That doesn’t mean it’s in any way the best or even a good approach to the problem.
They need three groups of supplies. The majority of supplies should go the least expensive route and be waiting on the surface. Otherwise they need enough supplies with them to make it to mars orbit and a short stay. Then they need enough supplies with them in the lander to get to their surface supplies.
The latest numbers I’ve seen are $190m for 2500 kg to the martian surface on a SpaceX Mars One lander. The lander itself becomes a temporary shelter. Mars One intends to land four crew on such a lander.
Most of your fuel cost is to move the transport ship that goes from orbit to orbit.
One way to think about it is a FH is needed for about every 2 to 2.4 people.