It would be nice to get to Jupiter faster, but the problem I can see is that Clipper will never be a priority for SLS and it may get kicked off the launcher if it gets in the way of the manned missions. The other issue is that the reliability of SLS is questionable given the low flight rate. The current schedule has Clipper flying 2 and a half years after the first SLS, which is too long a gap between flights IMO.In the end, I think Clipper rides another vehicle.
Quote from: Don2 on 02/24/2018 07:40 PMIt would be nice to get to Jupiter faster, but the problem I can see is that Clipper will never be a priority for SLS and it may get kicked off the launcher if it gets in the way of the manned missions. The other issue is that the reliability of SLS is questionable given the low flight rate. The current schedule has Clipper flying 2 and a half years after the first SLS, which is too long a gap between flights IMO.In the end, I think Clipper rides another vehicle. The sooner that decision is made the better.
One wonders how SLS is supposed to be certified by then.
From another topic:MATTBLACK:Yes - things would certainly look good for lunar missions, doing 'distributed launch' of the spacecraft and the Earth Departure Stage (EDS). A Falcon 9 could place a 20 ton Lander or Command Module type vehicle into orbit first. A Falcon Heavy places it's upper stage as an EDS into orbit next, where it's only payload is propellant (65-70 tons?) and a docking mechanism. The spacecraft docks with this and the EDS burns for TLI.Why not use the scheme for Europa Clipper?Can Atlas 401/F9 and F9H provide direct flight to Jupiter?
In a presentation at a meeting of the Committee on Astrobiology and Planetary Science of the National Academies March 28, Kevin Hand of the Jet Propulsion Laboratory said that feedback from a mission concept review for the proposed lander last June led to changes in the design to reduce its cost.“The technology and science were well received. The marching orders that we got out of that review were to see if we could simplify the architecture to reduce complexity and cost,” he said. While there’s been little discussion of the lander’s cost, Hand said there was a “desire” to reduce its cost to below $3 billion.The concept for the mission presented at that review involved the launch of the lander on a Space Launch System rocket no earlier than late 2025. The spacecraft would enter orbit around Jupiter in 2030 with a landing on Europa to follow no earlier than December 2031. The battery-powered lander would operate on the surface for at least 20 days, relying on a communications relay spacecraft in orbit to return data to Earth.
Twenty days on the surface doesn’t seem all that much for the time and money invested.
Another factor that enables the change in design, he said, is a shift in the science requirements for the lander. A report by a science definition team last year had included, as one of the mission’s priorities, the ability of the lander’s instruments to directly detect any life that might exist in the moon’s icy surface.“That’s a very high bar,” Hand said. “That bar runs the risk of setting expectations too high, perhaps, and also potentially cannibalizing some of the other science that the community sees as very valuable.”Instead, the mission team looked at what the “sweet spot” for science from the lander mission might be. Hand said that looking for biosignatures of past or present life would simplify the science requirements for the mission, including reducing the amount of data needed to be transmitted back to Earth.
So is the main part of the redesign to ditch the orbiting relay setup, leaving basically the descent module and the lander?
Quote from: redliox on 03/29/2018 10:34 PMSo is the main part of the redesign to ditch the orbiting relay setup, leaving basically the descent module and the lander?The briefing was at one of our meetings that just ended today. The Europa lander is going through a lot of redesign. The big change was to get rid of the orbiter, but they've also changed the science focus a lot. The goal is to both get the cost down and to broaden the mission because the focus on finding life was considered too narrow. There are some interesting animations as well. The lack of data about the surface makes landing really challenging, so one of their goals is to develop a very smart landing system that can choose the best landing site in real time.
Impactors have been crashed into asteroids to create a temporary plume of material from just under the surface. A, plume the composition of which could be identified by spectroscopy. Could this also be done on the largest airless bodies, like Europa, or is the surface gravity too strong? (I suppose collecting orbiting ejecta for sample return is way too acrobatic).
OIG announces an audit to assess NASA’s management of its mission to Europa, a moon of Jupiter.
Quote from: clongton on 02/24/2018 09:01 PMQuote from: Don2 on 02/24/2018 07:40 PMIt would be nice to get to Jupiter faster, but the problem I can see is that Clipper will never be a priority for SLS and it may get kicked off the launcher if it gets in the way of the manned missions. The other issue is that the reliability of SLS is questionable given the low flight rate. The current schedule has Clipper flying 2 and a half years after the first SLS, which is too long a gap between flights IMO.In the end, I think Clipper rides another vehicle. The sooner that decision is made the better.One of the biggest impediments to the program moving forward at the moment is SLS. Once they can move it elsewhere the better.
Quote from: rcoppola on 12/16/2014 04:40 PMThanks for the response. In reference to the launcher decision... I imagine that "if" the SLS could cut the transit time in half, that would certainly alter how they architect the systems? Or no?Absolutely. First of all, if EC does not have to do the Venus flybys, then they can take off the thermal protection. So how long do they keep designing the vehicle with thermal protection and without it? That's two designs, more money, etc.Also, a much shorter trip time may affect how much they have to test the spacecraft. But that could be a tricky issue. I'll provide a caveat that I'm not an expert on any of that stuff (remember, I'm a policy wonk), but generally a lot of testing is for lifetime. So they test something to see how long it will last. And if they can test it for a shorter lifetime that costs less.
Thanks for the response. In reference to the launcher decision... I imagine that "if" the SLS could cut the transit time in half, that would certainly alter how they architect the systems? Or no?
Quote from: vjkane on 05/21/2016 03:27 PMQuote from: redliox on 05/21/2016 09:00 AMCost is probably the true issue for flying via SLS. For the Europa mission (either the orbiter or lander), it would be wonderful to get directly to Jupiter; bad news is it may cost a lot, which coupled with safety was also a reason satellite providers rapidly abandoned the space shuttle. I'd like to see the flyby-orbiter fly with it, but I wouldn't want to do that with the lander since developing that will be enough of a future expense as is.I've worked with enough finance people to know that there is a lot of leeway on how costs are accounted for. NASA will have large fixed costs for maintaining the capability of launching SLS missions. Then there will be the marginal costs associated with building an individual booster, transporting it, fueling it, launching it, etc. The key will be whether the science division (I suspect there are some great telescope observatories that SLS could launch in addition to planetary missions) is charged only the marginal cost or a substantial portion of the fixed costs.I strongly suspect that NASA will design planetary missions so they can also be launched on commercial systems. SLS may not work. Political support may dry up (when will Shelby retire?). There could be a launch failure and the whole system stands down for a couple of years. Backups are good.In the case of the Europa multiflyby mission, a key decision will be whether to expand the fuel tanks or not and/or design the spacecraft for the heat of Venus gravity assists. The former would allow a deep space maneuver that would shorten the flight to 4.7 years with a Delta IV Heavy. The latter would allow an EVEEGA trajectory and a 7.4 year flight. How much insurance will NASA buy?I heard someone say that they're designing it for the thermal effects of a Venus flyby no matter what. I don't know why, but myabe the margins opened up and they figured it is better to just plan for that no matter what.
Quote from: redliox on 05/21/2016 09:00 AMCost is probably the true issue for flying via SLS. For the Europa mission (either the orbiter or lander), it would be wonderful to get directly to Jupiter; bad news is it may cost a lot, which coupled with safety was also a reason satellite providers rapidly abandoned the space shuttle. I'd like to see the flyby-orbiter fly with it, but I wouldn't want to do that with the lander since developing that will be enough of a future expense as is.I've worked with enough finance people to know that there is a lot of leeway on how costs are accounted for. NASA will have large fixed costs for maintaining the capability of launching SLS missions. Then there will be the marginal costs associated with building an individual booster, transporting it, fueling it, launching it, etc. The key will be whether the science division (I suspect there are some great telescope observatories that SLS could launch in addition to planetary missions) is charged only the marginal cost or a substantial portion of the fixed costs.I strongly suspect that NASA will design planetary missions so they can also be launched on commercial systems. SLS may not work. Political support may dry up (when will Shelby retire?). There could be a launch failure and the whole system stands down for a couple of years. Backups are good.In the case of the Europa multiflyby mission, a key decision will be whether to expand the fuel tanks or not and/or design the spacecraft for the heat of Venus gravity assists. The former would allow a deep space maneuver that would shorten the flight to 4.7 years with a Delta IV Heavy. The latter would allow an EVEEGA trajectory and a 7.4 year flight. How much insurance will NASA buy?
Cost is probably the true issue for flying via SLS. For the Europa mission (either the orbiter or lander), it would be wonderful to get directly to Jupiter; bad news is it may cost a lot, which coupled with safety was also a reason satellite providers rapidly abandoned the space shuttle. I'd like to see the flyby-orbiter fly with it, but I wouldn't want to do that with the lander since developing that will be enough of a future expense as is.
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