Conservatism and innovation in spacecraft design Options

[Doug M.]

Would it be fair to say that we're in the middle of a fairly conservative period with regard to spacecraft design? By this I mean that we haven't seen major innovations in propulsion, communications, power sources, shielding or avionics in the last decade, and we're not expecting to see major innovations in these areas in the next ten years. We are seeing a lot of ongoing advances in mission design, in payload, and in instrumentation. But the spacecraft themselves are changing much more slowly, and their design is increasingly dominated by heritage technologies.

Would this be a broadly true statement, or is there actually a lot of significant innovation in these areas that's going underreported? I'm sincerely curious.


Doug M.

[djellison]

By this I mean that we haven't seen major innovations in propulsion, communications, power sources, shielding or avionics in the last decade,

Last decade alone.....

Communications:
MRO transmitting at up to 6 Mbits/sec ( 40x the rate of previous Mars orbiters ) from Mars
MSL UHF relay at up to 2 Mbits/sec - 8x the rate of MER->ODY
LASER demo from LADEE at 620 Mbits/sec
OPALS about to be tested on ISS
Continued transition towards more Ka band 32Ghz DSN comms.

Power Sources
Increasingly efficient solar arrays enabling the first dedicated Jovian mission to fly with Solar Power ( Juno )
Development of the ASRTG ( currently on hold, but near completion )

Propulsion
Dawn's Ion engine has given it more than 6km/sec of Delta V - more than any other spacecraft in history -and may reach a total of 10km/sec
First interplanetary solar sail ( IKAROS )

Shielding
Juno's vault
Orion spacecraft student lead shielding experiment

Avionics
Transition from RAD6000 to RAD750
New avionics of SpaceX Falcon 9/Dragon (triple redundant with much COTS hardware)

Plus:
LDSD program including SIAD test program for increased EDL capacity to Mars ( potentially doubling the delivery mass of an MSL EDL like architecture )
Continued revolution in miniaturization. RACE scientific cubesat (among many, many others) , the INSPIRE cubesat BEO program.
HD color video from the surface of Mars. 1600 x 1200 MARDI movie.
Proven EDL performance increased from a 400lb rover in 2004 to a 2000lb rover in 2012


Is your statement broadly true? No. Not even slightly.

[Doug M.]

I'm delighted by djellison's response, since there's a lot of stuff here I wasn't aware of. That said, I think some items on his list are a bit speculative. I believe that OPALS is still in development. So while it is certainly worth mentioning, it probably shouldn't be given as much weight as stuff that's been tried (even in prototype) and has actually worked. SIAD, even more so: I believe that the first high-atmosphere test of that system will come later this year. Well and good, and I hope it works, but there's many a slip etc.; I don't think you can claim something as an advance in spacecraft design until someone has actually put it on a spacecraft.

Dawn's ion propulsion is great, but ion engines have been around for a while. Dawn's thrusters, in particular, are modified versions of the thrusters from Deep Space, launched in 1998. In the Dawn white paper way back in 2005, Marc Rayman and the other authors made a point of emphasizing just how innovative they weren't.

IKAROS was certainly innovative, but it's not exactly an innovation that's been seized on with enthusiasm. There was Nanosail D2, and then Sunjammer got cancelled, and there's crowdfunded Lunarsail which IMS is supposed to launch in late 2016, and then... well, that's about it. The major space agencies' attitude towards solar propulsion seems to be profound disinterest.

As to the Advanced Stirling RTG, "currently on hold" seems a somewhat optimistic interpretation of its status. My understanding is that it's more like "cancelled with little hope of a reprieve". If I'm wrong about that I welcome correction. (I'd like to be wrong, since a better RTG would indeed be a great step forward.)


Doug M.

[djellison]

I believe that OPALS is still in development.

It was launched two weeks ago. It is currently hanging off the side of the ISS waiting for final installation later this week before being powered-up on Saturday.

SIAD, even more so: I believe that the first high-atmosphere test of that system will come later this year.

Both heatshield and parachute's have already been thru initial testing.
https://www.youtube.com/watch?v=3YVOpdqdULU and https://www.youtube.com/watch?v=_jOzxEOlDJg

The first of three atmospheric tests comes later this year.

Dawn's ion propulsion is great, but ion engines have been around for a while. Dawn's thrusters, in particular, are modified versions of the thrusters from Deep Space, launched in 1998.

I know. Dawn increases upon the Delta V of DS1 by nearly an order of magnitude. 1.3km/sec -> 10km/sec. That's revolutionary.

IKAROS was certainly innovative, but it's not exactly an innovation that's been seized on with enthusiasm.

Wrong. The only reason Sunjammer may not fly is budgetary - not conservative engineering or 'enthusiasm'.

There is no shortage of new technology and innovation in spaceflight.

All this stuff is a simple Google away.

We are in a genuinely exciting period of technological innovation in just about every aerospace engineering discipline. The stories are out there if you care to look for them.

I would urge you to do a little research of your own - and ponder Mike's question

What would you give as an example of a less conservative period?