Onwards to Uranus and Neptune! Options

[vjkane]

I'm just absorbing the fact that a 14-year mission launched in 2035 (the latest date mentioned) would enter its extended mission just after I turn 90.

Youngster.

[infocat13]

recent updates and white papers on proposed Uranus and Neptune missions

http://www.spacepolicyonline.com/pages/ima...s%20Orbiter.pdf


http://www.spacepolicyonline.com/pages/ima...n%20Concept.pdf
this one is the Argos mission in its latest version, it might make it as a new frontiers mission.competition for the ASRG's for the Argos mission would come from a sample return flyby through the geysers of Enceladus mission being proposed!

[Greg Hullender]

I've been curious whether a Falcon 9 or Falcon 9 Heavy could improve the Argos mission, but this was the first time I actually saw an estimate for the cost of the launcher spelled out in the proposal. I notice that they don't mention either as a possiblity, but I figure a Falcon 9 could save $165M and a Falcon 9 Heavy could save $110M and increase the payload into the bargain.

To arrive at this, I started with their report. On page 58, they talk about mission concepts using the "smallest" Atlas V, a "mid-sized" one and the "largest" with a Star-48 upper stage. For each, they give a mass that could be delivered to a particular C3 (hyperbolic excess velocity squared). Figuring the smallest to be the 401 the medium to be the 541, and the largest to be the 551, and using the Atlas V numbers from Wikipedia, I figure one can convert from mass-to-GTO into mass-to-C3 if you multiply by 5 and divide by the desired C3.

Taking the Falcon 9 numbers from Wikipedia, the Falcon 9 could deliver slightly less payload than the Atlas V 401 (making it viable for the C3=25 scenario) while the Falcon 9 Heavy could deliver over 600 kg for the C3=162 scenario -- a big increase over the 478 kg scenario in the paper.

On page 63, they give a $200M estimate for the 551 with Star-48, $190M for 541, with $10M being the cost of the Star-48. Falcon 9 is only $35M and Falcon 9 Heavy is quoted at just $90M.

Of course, the Falcon 9 Heavy hasn't launched yet, so I could see not wanting to risk anything on it. Also, it seems they're currently not required to include the launch vehicle cost to get under the New Frontiers spending cap. Still, I'm surprised they included so many other options but left this one out.

Maybe once a Falcon 9 actually launches we'll see some proposals start to include it.

--Greg

[nprev]

I don't think anyone would ever submit a mission proposal with total cost estimates based on the manufacturer-projected price of an as-yet unproven booster, Greg. That would really be doubling down on assumed risk; NASA probably wouldn't even bother to finish reading the proposal once they saw that.

[Greg Hullender]

I wouldn't expect it to be the main proposal, but I'm still a bit surprised not to see it mentioned at all -- if only to show that the stated cost is conservative.

To turn it around, I'll be curious to see at what point we DO start seeing Falcons in the proposals.

--Greg

[machi]

What is really interesting is accessibility of Eris in Argo mission.

[ngunn]

But no mention of how long it would take to get there? Just 'date of KBO arrival depends on which KBO is chosen.' Mmm . .

[machi]

I think around another ~20 years (29 years after start). I suppose, that it's technically possible after some closer KBO flyby like mission of opportunity (or more precisely mission of survive).

[Greg Hullender]

I can't find a figure for Argos' expected final speed, but if we take Voyager 2's average speed from Earth to Neptune (19 km/sec) and divide that into the difference between Neptune (30.1 AU) and Eris (96.7 AU) I come up with 16.7 years. That's very crude, of course (Neptune and Eris aren't aligned THAT well and the speed PAST Neptune must be a good bit slower than the speed before it) but I'd say that's got to be a lower bound. Even 20 years seems optimistic.

Eris is just too far.

--Greg

http://voyager.jpl.nasa.gov/science/neptune.html is my reference for 19 km/sec.

[elakdawalla]

"mission of survive"

I like that terminology! But don't think it's one NASA will be adopting any time soon

[punkboi]

I wouldn't expect it to be the main proposal, but I'm still a bit surprised not to see it mentioned at all -- if only to show that the stated cost is conservative.

To turn it around, I'll be curious to see at what point we DO start seeing Falcons in the proposals.

--Greg

I assume it won't be till after 2011...when Falcon proves its mettle in safely delivering cargo (and/or crew) to the ISS.

[ugordan]

I assume it won't be till after 2011...when Falcon proves its mettle in safely delivering cargo (and/or crew) to the ISS.

There's more to it than just the price of a launch vehicle, some payloads for example impose requirements like vertical integration (F9 is integrated horizontally), access to payload at all times before launch campaign without needing to say destack the vehicle, ground support equipment requirements, etc.

SpaceX was awarded a NASA's Launch Services contract two years ago and they're still yet to win a launch contract. Atlas V still wins payloads even though it is overpowered for some of the spacecraft (with Delta II being phased out and becoming too expensive), F9 is still too risky and unproven. Keep in mind F9 price down the road also needs to stabilize once the vehicle becomes operational and true costs become clear.

[qraal]

There's more to it than just the price of a launch vehicle, some payloads for example impose requirements like vertical integration (F9 is integrated horizontally), access to payload at all times before launch campaign without needing to say destack the vehicle, ground support equipment requirements, etc.

SpaceX was awarded a NASA's Launch Services contract two years ago and they're still yet to win a launch contract. Atlas V still wins payloads even though it is overpowered for some of the spacecraft (with Delta II being phased out and becoming too expensive), F9 is still too risky and unproven. Keep in mind F9 price down the road also needs to stabilize once the vehicle becomes operational and true costs become clear.

Nice to see Musk's bird finally took wing and they've won the Iridium upgrade contract. Of course there's no such thing as statistics based on one example, thus the next few launches will be watched very carefully indeed.

Need I say it? Go ARGOS!

[antipode]

The F9 is going to need an EDS - what are they thinking of? One of the Star solids?
Even then I cant see the F9 being up to an outer planets mission unless the trajectory is a LOOONG one

P

[ugordan]

F9 doesn't inherently need an "EDS" any more than Atlas V needs one. The upper stage has performance for an escape trajectory. The problem as you say is it lacks performance required for outer planet missions. In terms of C3 energy capability, F9 is somewhere between a Delta II and a vanilla Atlas V 401. For comparison, New Horizons used 5 solids on the boosters and an additional solid kick stage and JUNO will use 4 solids IIRC.

Theoretically, a F9 Heavy could do it, but with 27 engines and being very much a paper rocket, it's only a theoretical what-if.
I can see F9 winning Discovery class missions in the future, New Frontiers missions will still be ruled by Atlas.