China plans to launch Mars Probe by 2020

[billbobjebkirk]

http://gbtimes.com/china/china-racing-make-2020-launch-window-mars

Forgive me if this has already been posted, but I didn't see a topic for it.

So, China is planning on launching their second ever attempt at Mars, and it looks pretty ambitious. Their design ahs both an orbiter and a rover, which will carry similar ground-penetrating radar as the Yutu rover from 2013. I must say, if this succeeds, It's going to be a major boost for China's already growing ambitions. Politics aside, what are your thoughts?

Edited February 26, 2016 by billbobjebkirk

[_Augustus_]

China is going to Mars with a probe because everyone else does it. Their human destination, though, is Ceres. 

[Spaceception]

11 minutes ago, _Augustus_ said:

Their human destination, though, is Ceres. 

Really? Links?

[_Augustus_]

Just now, Spaceception said:

Really? Links?

https://en.wikipedia.org/wiki/Sample_return_mission

Somewhere in there. It's obvious that they want to be the first to land on something, and there's no way to beat the US to Mars.

[Spaceception]

48 minutes ago, billbobjebkirk said:

http://gbtimes.com/china/china-racing-make-2020-launch-window-mars

Forgive me if this has already been posted, but I didn't see a topic for it.

So, China is planning on launching their second ever attempt at Mars, and it looks pretty ambitious. Their design ahs both an orbiter and a rover, which will carry similar ground-penetrating radar as the Yutu rover from 2013. I must say, if this succeeds, It's going to be a major boost for China's already growing ambitions. Politics aside, what are your thoughts?

Hey, it looks like the 2020s will be "The Mars decade" Mars 2020 rover, (Possible) SpaceX Mars colony, Phooprint (ESA) Not to mention the several missions between now and 2020, and now this.

Are there any other Mars missions in the 2020s?

5 minutes ago, _Augustus_ said:

https://en.wikipedia.org/wiki/Sample_return_mission

Somewhere in there. It's obvious that they want to be the first to land on something, and there's no way to beat the US to Mars.

Thanks

Edited February 26, 2016 by Spaceception

[billbobjebkirk]

7 minutes ago, Spaceception said:

Hey, it looks like the 2020s will be "The Mars decade" Mars 2020 rover, (Possible) SpaceX Mars colony, Phooprint (ESA) Not to mention the several missions between now and 2020, and now this.

Are there any other Mars missions in the 2020s?

Sample return? (Begins praying) Also, I think NASA plans on sending some preliminary testing missions in the late 2020s for their manned program, but who knows about that.

Edited February 26, 2016 by billbobjebkirk

[fredinno]

9 hours ago, billbobjebkirk said:

http://gbtimes.com/china/china-racing-make-2020-launch-window-mars

Forgive me if this has already been posted, but I didn't see a topic for it.

So, China is planning on launching their second ever attempt at Mars, and it looks pretty ambitious. Their design ahs both an orbiter and a rover, which will carry similar ground-penetrating radar as the Yutu rover from 2013. I must say, if this succeeds, It's going to be a major boost for China's already growing ambitions. Politics aside, what are your thoughts?

I don't say it's impossible- a discovery-class mission should be possible in that timeframe with the proper cash. Honestly, China could really get a niche in the space arena with its relatively low budget if it focussed on robotic missions (like ESA, but hopefully, more money will push those plans beyond)

9 hours ago, _Augustus_ said:

https://en.wikipedia.org/wiki/Sample_return_mission

Somewhere in there. It's obvious that they want to be the first to land on something, and there's no way to beat the US to Mars.

I disagree. NASA Mars plans are a f**king monster, with 7+ SLS per mission and construction staging in lunar orbit. It's not happening, and NASA knows it, unless a space race 2.0 happens. Even Ceres would likely be easier- so long as you can make a ultra-high thrust nuclear-ion drive (the oligarchy of China allows for such projects to take place without public outroar cancelling it, unlike in the US, where you'd be hard-pressed to fund such a thing), and ultra-long duration travel (bring a LOT of supplies!). You don't even need artifical-G, since Ceres has literally no gravity.

9 hours ago, Spaceception said:

Hey, it looks like the 2020s will be "The Mars decade" Mars 2020 rover, (Possible) SpaceX Mars colony, Phooprint (ESA) Not to mention the several missions between now and 2020, and now this.

Are there any other Mars missions in the 2020s?

Thanks

Nah, Phootprint is 2024.https://en.wikipedia.org/wiki/Phootprint However, Mars is also getting Mars Hope (Muslim Mars Probe).

[NovaSilisko]

On 2/27/2016 at 11:13 PM, fredinno said:

ultra-high thrust nuclear-ion drive

What's an ultra-high thrust nuclear ion drive?

 

On 2/27/2016 at 11:13 PM, fredinno said:

You don't even need artifical-G, since Ceres has literally no gravity.

What? Its surface gravity is 0.029g. About 20% of the Moon's. Small, but not low enough to ignore.

Why, though, would having low/no surface gravity remove any requirement for artificial gravity anyway?

Edited March 1, 2016 by NovaSilisko

[fredinno]

2 hours ago, NovaSilisko said:

What's an ultra-high thrust nuclear ion drive?

 

What? Its surface gravity is 0.029g. About 20% of the Moon's. Small, but not low enough to ignore.

Why, though, would having low/no surface gravity remove any requirement for artificial gravity anyway?

A (much) higher thrust ion drive powered by nuclear fission reactors are ultra-high thrust nuclear ion drives. One canidate would be a high-thrust VASMIR with a nuclear fission reactor (the sun is too low at ceres distance)

And Ceres gravity is low enough that you can still dock to it and forgo the lander entirely- assuming you have good enough retrothrusters and ladning legs on your spacecraft.

Also, the artifical gravity would not be required in a very-low G destination- it would be like 0G for the most part, and minimal adaption to Ceres gravity would be needed. It would be bad for the astronauts when they return to Earth, but the lack of artif-G would not be an issue affecting the mission itself. It's like Zubrin's MAV not using any Artif. Gravity- it sucks, but is standable since any problems from the reintroduction of G can be fixed whenthe astronaut returns to Earth. Artif. G is heavily desirable for a Ceres mission, but not necessary, unlike on Mars, where the astronauts need to be accustomed to that gravity beforehand to maximise efficiency of the mission.

[Streetwind]

10 hours ago, NovaSilisko said:

What's an ultra-high thrust nuclear ion drive?

A thing that does not and will never exist because ion/plasma thrusters don't work that way. Despite whatever @fredinno may be hoping for

Modern plasma thrusters can produce somewhere between 0.025 N/kW at ~5000s Isp (VASIMR) and 0.01 N/kW at ~19,000s Isp (DS4G prototype); and both of these systems operate at or beyond 200 kW in power already. Compare the Dawn probe's NSTAR thruster, based on 30 year old technology and 2.1 kW of total power, which puts out 0.043 N/kW at 3100s Isp. You should immediately notice two things: 1.) technological advancement does not really improve electric engine thrust per kW in any measurable way, and 2.) upping total system power does not really improve electric engine thrust per kW in any measurable way either. Isp does increase, improving the total thrust/Isp/power ratio, but upping thrust alone? That basically doesn't happen unless you're willing to give up nearly all your Isp for it. And if you do, chemical engines might be a better solution for you... The technology here is maxed out. This is why an "ultra-high thrust nuclear ion drive" does not and will not ever exist.

However, that doesn't mean you can't get better spacecraft TWR with plasma thrusters. It's just that the thrusters themselves are largely irrelevant in that development. What you need instead is a higher spacecraft specific power (the ratio of power output to mass dedicated to it). The main reason electric engines haven't taken over everything deep space related already is because we have no power systems suitable to drive them. We can basically choose between solar - which stops working beyond the asteroid belt - and, well... crickets chirping. And the thing about solar is that it produces completely the wrong voltage for such an engine, which necessitates a so-called PDU (power distribution unit). Most spacecraft carry small PDUs for their onboard systems, but in order to feed an electric engine, a PDU must be large. It can weigh as much as the solar panels themselves. In other words, specific power of solar electric propulsion solutions is halved from the theoretical value before the spacecraft even leaves Earth orbit and further loses power as it travels away from the sun.

If you want to build great spacecraft with ion drives, you therefore need to massively increase research in power production methods, and into building better PDUs. If you can halve the weight of your power production solution at identical power output (doubled specific power), you can add a second plasma thruster, and you've just doubled your thrust while keeping the spacecraft's weight constant. That's a real, significant TWR advantage you can achieve with new technology.

As for where we currently are in terms of specific power... it's super hard to find up to date numbers, because the solutions are almost always specific to individual spacecraft. Also, technology launched into space is rarely on the bleeding edge of research, because it can take 5-10 years to actually build and launch the craft. But for example, the Curiosity rover's RTG is specced at 2.5 W/kg, decreasing over time. The Juno probe currently going to Jupiter, which has some of our best solar panels ever deployed in space, has panels specced around 39 W/kg - in Earth orbit. At Jupiter, only 1.4 W/kg will be left, barely half of what a RTG with the same power output would manage. And that's still without the mass of a PDU factored in, which (as mentioned) for a solar electric propulsion spacecraft can as much as halve the specific power. Finally, a small experimental nuclear reactor that NASA toyed with some 10-15 years ago, the SAFE-400, was specced at up to 195 W/kg... without factoring in mass for a space-worthy cooling system, and again, without a PDU. It also had only 2-3 years of usable lifespan at that power level.

 

A speculative side note: Dr. Harold White, the crazy guy at NASA Eagleworks that claims that yes, quantum thrusters are real and he's brought them to TRL 3 already, says that he expects a "lower bound" of 0.1 N/kW for this technology. That would basically equate to roughly an order of magnitude more thrust for the same power input than our current plasma thrusters, all without requiring any fuel. Now if this left the realm of science fiction and could actually be built, that would be a huge breakthrough in electric propulsion and seriously open up the solar system. Spacecraft would have much higher TWR due to being able to ditch all fuel in addition to requiring much less mass dedicated to power production and/or mounting more engines... and they'd be able to burn until the systems break down from wear and tear. Sadly, as a realist, I'm forced to say "test stand results or it didn't happen" And it'll be many years yet until Eagleworks gets that far even IF the technology is valid.

Edited March 2, 2016 by Streetwind

[fredinno]

1 hour ago, Streetwind said:

A thing that does not and will never exist because ion/plasma thrusters don't work that way. Despite whatever @fredinno may be hoping for

Modern plasma thrusters can produce somewhere between 0.025 N/kW at ~5000s Isp (VASIMR) and 0.01 N/kW at ~19,000s Isp (DS4G prototype); and both of these systems operate at or beyond 200 kW in power already. Compare the Dawn probe's NSTAR thruster, based on 30 year old technology and 2.1 kW of total power, which puts out 0.043 N/kW at 3100s Isp. You should immediately notice two things: 1.) technological advancement does not really improve electric engine thrust per kW in any measurable way, and 2.) upping total system power does not really improve electric engine thrust per kW in any measurable way either. Isp does increase, improving the total thrust/Isp/power ratio, but upping thrust alone? That basically doesn't happen unless you're willing to give up nearly all your Isp for it. And if you do, chemical engines might be a better solution for you... The technology here is maxed out. This is why an "ultra-high thrust nuclear ion drive" does not and will not ever exist.

However, that doesn't mean you can't get better spacecraft TWR with plasma thrusters. It's just that the thrusters themselves are largely irrelevant in that development. What you need instead is a higher spacecraft specific power (the ratio of power output to mass dedicated to it). The main reason electric engines haven't taken over everything deep space related already is because we have no power systems suitable to drive them. We can basically choose between solar - which stops working beyond the asteroid belt - and, well... crickets chirping. And the thing about solar is that it produces completely the wrong voltage for such an engine, which necessitates a so-called PDU (power distribution unit). Most spacecraft carry small PDUs for their onboard systems, but in order to feed an electric engine, a PDU must be large. It can weigh as much as the solar panels themselves. In other words, specific power of solar electric propulsion solutions is halved from the theoretical value before the spacecraft even leaves Earth orbit and further loses power as it travels away from the sun.

If you want to build great spacecraft with ion drives, you therefore need to massively increase research in power production methods, and into building better PDUs. If you can halve the weight of your power production solution at identical power output (doubled specific power), you can add a second plasma thruster, and you've just doubled your thrust while keeping the spacecraft's weight constant. That's a real, significant TWR advantage you can achieve with new technology.

As for where we currently are in terms of specific power... it's super hard to find up to date numbers, because the solutions are almost always specific to individual spacecraft. Also, technology launched into space is rarely on the bleeding edge of research, because it can take 5-10 years to actually build and launch the craft. But for example, the Curiosity rover's RTG is specced at 2.5 W/kg, decreasing over time. The Juno probe currently going to Jupiter, which has some of our best solar panels ever deployed in space, has panels specced around 39 W/kg - in Earth orbit. At Jupiter, only 1.4 W/kg will be left, barely half of what a RTG with the same power output would manage. And that's still without the mass of a PDU factored in, which (as mentioned) for a solar electric propulsion spacecraft can as much as halve the specific power. Finally, a small experimental nuclear reactor that NASA toyed with some 10-15 years ago, the SAFE-400, was specced at up to 195 W/kg... without factoring in mass for a space-worthy cooling system, and again, without a PDU. It also had only 2-3 years of usable lifespan at that power level.

 

A speculative side note: Dr. Harold White, the crazy guy at NASA Eagleworks that claims that yes, quantum thrusters are real and he's brought them to TRL 3 already, says that he expects a "lower bound" of 0.1 N/kW for this technology. That would basically equate to roughly an order of magnitude more thrust for the same power input than our current plasma thrusters, all without requiring any fuel. Now if this left the realm of science fiction and could actually be built, that would be a huge breakthrough in electric propulsion and seriously open up the solar system. Spacecraft would have much higher TWR due to being able to ditch all fuel in addition to requiring much less mass dedicated to power production and/or mounting more engines... and they'd be able to burn until the systems break down from wear and tear. Sadly, as a realist, I'm forced to say "test stand results or it didn't happen" And it'll be many years yet until Eagleworks gets that far even IF the technology is valid.

I meant HIGHER thrust ION drives. By that, I was more thinking a cluster of VASMIR. That's why I said VASMIR was a canadiate, but if it had a higher-higher thrust mode of say, 3000-4000s isp.

Is that needed to be any more clear?

[Streetwind]

27 minutes ago, fredinno said:

I meant HIGHER thrust ION drives. By that, I was more thinking a cluster of VASMIR. That's why I said VASMIR was a canadiate, but if it had a higher-higher thrust mode of say, 3000-4000s isp.

Is that needed to be any more clear?

Yes because it apparently confused at least one reader.

The point I'm making is, your choice of electric engine is largely irrelevant in determining your total vessel TWR. But your power solution, that matters absolutely. From what you wrote, you seem to agree that we ought to be investing more effort into spacecraft sized nuclear reactors.

[fredinno]

3 minutes ago, Streetwind said:

Yes because it apparently confused at least one reader.

The point I'm making is, your choice of electric engine is largely irrelevant in determining your total vessel TWR. But your power solution, that matters absolutely. From what you wrote, you seem to agree that we ought to be investing more effort into spacecraft sized nuclear reactors.

Nuclear reactors are essential past Mars, TBH.