Nasa announces new rover mission to Mars in 2020 Options

[atomoid]

...we can see in great detail on PIA23823 one can sort of work out how it is released and rotated to the surface by the actuators and hinges etc

Great picture.. Its really quite a remarkably beautiful piece of equipment thats larger than it appears, and fun to guess what the sequence will be, so im guessing the legs self-deploy under their own spring tension, with the two legs we see on top have their actuators to release, most likely before the triangular hinge activates to rotate the craft 90 degrees, that rotation itself perhaps allows the bottom two legs to slide from their slots without actuators...well see.

[Hungry4info]

The helicopter drone now has a name: Ingenuity.

[PaulH51]

Here is the raw media reel on YouTube... We can see the Delivery Sytsem (release and deploy) beginning at the 5:12 time stamp

link

[PaulH51]

Not yet confirmed by NASA, but it appears that the launch date for the Mars 2020 mission is expected to slip to July 20 due to a “little bit of a hiccup” with Atlas 5 launch vehicle processing.

Apparently it was caused by an issue with a crane at the launch facility (see reply by ULA's Tory Bruno).

Refer to this Twitter thread LINK.

A screen capture of the thread is provided for those without Twitter.

[7B8]

Here is the raw media reel on YouTube... We can see the Delivery Sytsem (release and deploy) beginning at the 5:12 time stamp

link

Fascinating to see that video. Thanks for posting. At the end it shows some helicopter test flights on a very smooth and hard surface. The landing looks bouncy and fast. I assume the legs have been designed to prevent the helicopter from toppling over under most conditions. Still, I wonder, does anybody know if this has been tested on a sandy, bumpy surface with the occasionally rock to bump into? I tried to find any information/videos but without success.

[mcaplinger]

At the end it shows some helicopter test flights on a very smooth and hard surface. The landing looks bouncy and fast. I assume the legs have been designed to prevent the helicopter from toppling over under most conditions.

Those are early tests. I'm pretty confident that they have smoothed it out quite a bit. I've crashed more than my share of small helicopters and if they haven't smoothed it out since that video, it will tip over for sure on any natural terrain.

[centsworth_II]

Those are early tests. I'm pretty confident that they have smoothed it out quite a bit....

At 3:30 in the video there is a very well controlled vertical landing that is much different than those shown at the end of the video. I'm sure this is how the landings on Mars will be handled.

[Julius]

I have been reading up ahead of the launch and hopefully safe landing of Perseverance rover on Mars. I am surprised at the energy constraints the Curiosity rover had to work with given that 110 W are used to generate electricity for rover operations on the surface but a part of it also is' wasted' in keeping the rover parts warm. Has anything changed with the new Perseverance rover regarding energy usage ??

[vjkane]

I have been reading up ahead of the launch and hopefully safe landing of Perseverance rover on Mars. I am surprised at the energy constraints the Curiosity rover had to work with given that 110 W are used to generate electricity for rover operations on the surface but a part of it also is' wasted' in keeping the rover parts warm. Has anything changed with the new Perseverance rover regarding energy usage ??

RTG's work by having a strong difference in temperature between thermocouples: RTGs work by converting thermal energy into electrical energy through devices known as thermocouples. The natural decay of plutonium-238 produces heat that is then transferred to one side of the thermocouple. The temperature difference between the fuel and the atmosphere allows the device to convert this heat into electricity. The most current RTG model, the Multi-Mission Radioisotope Thermoelectric Generator (MMRTG), provides approximately 110 Watts of electrical power when freshly fueled. DOE webpage

To create the difference, there must be a *hot* heat source, in this case plutonium-238. Not all of the heat gets converted to electricity (3-4% as a I recall). You'll note the fins on the RTG unit as one part of this. However, rovers and spacecraft need to be kept warm inside, and so some of that heat is piped through the body. The benefit isn't trivial - half of the electrical power in the solar powered Juno spacecraft goes to heaters. (Missions can also request to use radioisotope heater units, are are basically units with a little Pu-238 in them that can provide heat. See the list of missions below that have used them.)

The Department of Energy (which develops RTG technology) is planning a new generation of RTGs to be available toward the end of this decade that would be around twice as efficient in converting the heat to electricity.

Missions that used RHUs:

NASA missions enabled by radioisotope heater units

Apollo 11 EASEP Lunar Radioisotope Heater - contained two 15W RHUs
Pioneer 10 & 11 - 12 RHUs each
Voyager 1 & 2 - 9 RHUs each
Galileo - 120 RHUs (103 on orbiter, 17 on atmospheric probe)
Mars Pathfinder Sojourner Rover - 3 RHUs
Cassini - 117 RHUs (82 on orbiter, 35 on Huygens Titan probe)
MER Spirit & Opportunity Rovers - 8 RHUs each

RHU webpage

[mcaplinger]

The RHU discussion is interesting but as noted neither MSL nor M2020 use them; they use a fluid loop that is directly heated by waste heat from the RTG, and electrical heaters for external components. AFAIK no non-rover has ever used a fluid loop, but I could be mistaken.

https://trs.jpl.nasa.gov/bitstream/handle/2...15-2733_A1b.pdf has a discussion of the fairly minor thermal-control changes between MSL and M2020.

[MahFL]

I have been reading up ahead of the launch and hopefully safe landing of Perseverance rover on Mars. I am surprised at the energy constraints the Curiosity rover had to work with given that 110 W are used to generate electricity for rover operations on the surface but a part of it also is' wasted' in keeping the rover parts warm. Has anything changed with the new Perseverance rover regarding energy usage ??

The energy is not really wasted, the motors and joints have to be warmed up to work correctly on Mars, as it gets extremely cold there at night, as there is virtually no atmosphere to regulate the night time temperatures.

[Paolo]

AFAIK no non-rover has ever used a fluid loop, but I could be mistaken.

IIRC Soviet probes of the 2MV and 3MV series (e.g. Zond 3) used fluid loops for thermal control

[mcaplinger]

IIRC Soviet probes of the 2MV and 3MV series (e.g. Zond 3) used fluid loops for thermal control

When I said "fluid loop" I meant "fluid loop heated by the RTG". Look at the Cassini and Galileo examples, that had big RTGs and a whole bunch of little RHUs, leaving all the RTG heat just being wasted into space. Of course fluid loops have their own problems.

The energy is not really wasted, the motors and joints have to be warmed up to work correctly on Mars...

Depends on your definition of "wasted". The original plan for MSL was to use dry lubricants that wouldn't require any heating to operate. This proved unworkable and was one of the major reasons for the launch slip from 2009 to 2011: see https://www.thespacereview.com/article/1319/1

[vjkane]

When I said "fluid loop" I meant "fluid loop heated by the RTG". Look at the Cassini and Galileo examples, that had big RTGs and a whole bunch of little RHUs, leaving all the RTG heat just being wasted into space. Of course fluid loops have their own problems.



Depends on your definition of "wasted". The original plan for MSL was to use dry lubricants that wouldn't require any heating to operate. This proved unworkable and was one of the major reasons for the launch slip from 2009 to 2011: see https://www.thespacereview.com/article/1319/1

I know that several proposals to the outer solar system have planned to use fluid loops.

[ADMIN- edited for accidental duplication of post]

[mcaplinger]

More information about the helicopter here: https://trs.jpl.nasa.gov/bitstream/handle/2...L%2317-6243.pdf