Fastest Spacecraft Ever?!?, Which one is it? Options

[Bob Shaw]

Who's up for Top Trumps. I think Alan just won.

Doug

Doug:

Not fair! Alan had his own rocket!

Bob Shaw

[David]

Not fair! Alan had his own rocket!

Er... and you were stuck with one you made out of a soapbox?

[djellison]

My Estes two-stage Mongoose would shame an Atlas V any day of the week

Doug

[ljk4-1]

Via Solar Array to the Outer Planets

New Scientist is covering the work of Rudolph Meyer (UCLA), who envisions a vehicle that sounds for all the world like a cross between a solar sail and an ion engine. And in a way, it is: Imagine a flexible solar panel a solid 3125 square meters in size, and imagine this ’solar-electric membrane’ weighing no more than 16 grams per square meter, far lighter than today’s technology allows. I’ll be anxious to see the paper when it’s published in Acta Astronautica, but the gist of the design seems to be this: the solar membrane would power an ion engine array which, conventionally enough, draws xenon ions through a powerful electric grid to create thrust.

The membrane, stabilized by additional ion engines at the corners, could reach remarkable speeds. Meyer talks about 666,000 kilometers per hour — that’s one year to Pluto, and an obvious invitation out into the Kuiper Belt. No show stoppers here, but clearly a design heavily dependent on advances in thin film arrays. I always listen to Geoffrey Landis (NASA GRC) about such matters; he is, after all, the man Robert Forward declared to be his successor in interstellar studies. And Landis is quoted as saying of Rudolph’s idea, “…the extremely high-energy ion-propulsion vehicles he proposes may be a practical alternative technology for future missions to the edge of interstellar space.”

Full article here:

http://www.centauri-dreams.org/?p=638

[djellison]

Meyer talks about 666,000 kilometers per hour — that's one year to Pluto,."

Yes - but how long to accelerate to 666000 kph ?

Doug

[ljk4-1]

Yes - but how long to accelerate to 666000 kph ?

Doug

I don't know. If anyone can find the paper or even just more
information on the plan, please post it here, thanks!

[Bill Harris]

...but, as importantly, how long to decelerate from 666000 kph ?

--Bill

[tty]

Also the payload would probably have to have some kind of spaced multiple shielding. At 185 kms-1 even micrometeorites would be deadly.

tty

[dvandorn]

Yeah -- you'd end up with a pretty ragged, hole-ridden sail/solar panel by the time you got out to the Kuiper Belt. How are you going to create a really, really thin/lightweight sail/solar panel that can stand up to the high-energy dust impacts it's going to face? Gonna redirect some of that energy into intense magnetic fields that divert dust particles electrostatically?

Before we get too involved in discussions of new propulsion technologies, I will make the cautionary noise, here, that when Mike Griffin went before Congress last week, he was asked point-blank about new propulsion technology research. He said that NASA's immediate goals (including the full range of VSE goals) do not require any new propulsion technologies. He said that almost every NASA program, with the exception of the Shuttle/ISS wind-down, has been cut or delayed, including propulsion technology research. He said that there will be *no* new propulsion research for a decade or more.

BTW, he also said that, since Congress and this Administration refused to give NASA any additional monies to repair damage to Michoud, the Stennis Space Center, and the Kennedy Space Center incurred during last year's hurricane season, he was even stealing from the Shuttle/ISS funds to cover a roughly half-billion-dollar repair bill.

-the other Doug

[ljk4-1]

Before we get too involved in discussions of new propulsion technologies, I will make the cautionary noise, here, that when Mike Griffin went before Congress last week, he was asked point-blank about new propulsion technology research. He said that NASA's immediate goals (including the full range of VSE goals) do not require any new propulsion technologies. He said that almost every NASA program, with the exception of the Shuttle/ISS wind-down, has been cut or delayed, including propulsion technology research. He said that there will be *no* new propulsion research for a decade or more.

What a frightening and depressing statement. Does Griffin think that just
because he won't let NASA engineers and space scientists develop new
concepts of propulsion that other equally talented and visionary people
in other countries won't pursue this course? Or that he might drive US
talent to more receptive places?

The next time I hear Griffin or anyone else say that the USA must remain
at the forefront of space exploration and technology, I will remember this
statement.

It will be sadly ironic if in 2025 we have a handful of astronauts on the
Moon while the other space nations are sending probes to every planet
in the Sol system and beyond.

[djellison]

he won't let

He has no money. Having been told to do X things, by date Y with Z dollars he has no options left but to cull a lot of other programs. It sucks, it is very wrong, but it is the only thing that he can do given the parameters than have been handed down to him from on high.

Doug

[Stephen]

What a frightening and depressing statement. Does Griffin think that just
because he won't let NASA engineers and space scientists develop new
concepts of propulsion that other equally talented and visionary people
in other countries won't pursue this course? Or that he might drive US
talent to more receptive places?

Why blame Griffin? These engineers and space scientists cannot develop new concepts of propulsion if Congress won't provide NASA with the funding necessary to allow them to proceed.

Unless, of course, you would prefer Griffin take more money from (say) space science to make up the shortfall.

It will be sadly ironic if in 2025 we have a handful of astronauts on the
Moon while the other space nations are sending probes to every planet
in the Sol system and beyond.

Well, America has already sent probes "to every planet in the Sol system and beyond", has it not? By sending probes out to those same planets those other space nations would merely be catching up.

What I presume you *really* mean--if, that is, those other nations are really going to steal a march on America--is that by 2025, when America (may) have "a handful of astronauts" plodding around on the Moon (much as once upon a time it had a handful paddling around in LEO aboard the ISS--until it was decided LEO was too boring a place and the Moon a more exciting destination) those other nations were planning to send astronauts of their own to destinations more exciting than the boring old Moon: "every planet in the Sol system and beyond".

That may well happen. After all, once upon a time Spain and Portugal led the way in Europe's exploration of the world, finding routes around the Cape of Hope to India and across the Atlantic to the New World. Yet eventually they were eclipsed by other European nations such as France and Britain. America (and Russia) would be merely following in their footsteps by commencing the world's exploration of outer space only to be eclipsed in time by johnny-come-latelies.

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Stephen

[ljk4-1]

My concern is that the VSE is going to become Apollo Mark 2, where it takes
away resources for real science missions just to put a few extra humans on
the Moon for slightly longer stays.

Then the politicians of 2020 or so decide it is not worth the effort, or the public
gets bored again, or both, and we end up with a few more flags and footprints,
the Moon is abandonded for another 40 years, manned Mars missions get
pushed even farther into the distant future, and robotic planetary missions
lose the momentum they had regained in the 1990s and 2000s. All for yet
another stunt to show the world just how great the USA is.

[djellison]

My concern is that the VSE is going to become Apollo Mark 2, where it takes
away resources for real science missions just to put a few extra humans on
the Moon for slightly longer stays.

'going to become'

It's already happened.
http://planetary.org/programs/projects/sos/

Doug

[Stephen]

My concern is that the VSE is going to become Apollo Mark 2, where it takes
away resources for real science missions just to put a few extra humans on
the Moon for slightly longer stays.

That sounds an awful lot like the grumbles you used to find (and maybe still find) on Usenet about the Apollo missions not being real science missions, usually from those seeking to show how unmanned missions do "real science" ever so much better.

Then the politicians of 2020 or so decide it is not worth the effort, or the public
gets bored again, or both, and we end up with a few more flags and footprints,
the Moon is abandonded for another 40 years, manned Mars missions get
pushed even farther into the distant future, and robotic planetary missions
lose the momentum they had regained in the 1990s and 2000s. All for yet
another stunt to show the world just how great the USA is.

If the VSE were only "another stunt to show the world just how great the USA is" America would not be sending people back to the Moon. It would be sending them straight to Mars instead.

The real danger from the politicians to the VSE (IMO) is that:

1. They may wind it back before the first CEV is even sent to the Moon (much as their funding cuts forced changes to the Shuttle and the ISS).
2. If the Moon is reached, the politicians--be it the president or Congress or both--may give NASA an unwelcome choice: you can keep going to the Moon or you start heading to Mars, but not both at the same time.

That last choice is arguably what happened to Apollo. The Apollo program died because America was not prepared to pay for a manned lunar program *and* the development of the Shuttle at the same time. NASA was allowed to do one or the other but not both. That naturally meant an invidious choice had to be made.

Compare that to the present situation since the VSE was announced. NASA is presently in more or less the position it would have faced in 1972 had the Shuttle been given the go-ahead while at the same time it has also been authorised to keep sending Apollo missions to the Moon for a few years longer--*but* without being given the funding necessary to fully cover both. It goes without saying that one consequence would surely have been that other NASA programs, especially expensive unmanned ones like Viking and Voyager with no connection to Apollo or to the Shuttle, would have been hit as NASA took funding from them to make up the shortfall in the Shuttle and/or Apollo programs.

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Stephen