Mission Proposal: Asteroid 16 Psyche - "Journey to the centre of the Earth"

[AJA]

This sounds very interesting...

http://www.newscientist.com/article/dn24793-astrophile-heavy-metal-asteroid-is-a-spacecraft-magnet.html?full=true&print=true#.UsWwLHntm_8

"It could be like a little refrigerator magnet in space," says Linda Elkins-Tanton of the Carnegie Institution in Washington DC, who presented an idea for a mission to Psyche at a meeting of the American Geophysical Union in San Francisco last week

Are the AGU slides posted on the web someplace? I only found the abstract on the AGU website (Presented on Dec 13th)

CONTROL ID: 1818610
TITLE: Journey to a metal world: Concept for a Discovery mission to Psyche
AUTHORS (FIRST NAME, LAST NAME): Daniel Wenkert¹, Linda T Elkins-Tanton², Erik I Asphaug³, Sarah Bairstow⁴, James F Bell⁵, David A Bercovici⁶, Bruce G Bills⁷, Richard P Binzel⁸, William F Bottke⁹, Insoo Jun¹⁰, Damon Landau¹¹, Simone Marchi¹², David Oh¹³, Benjamin P Weiss¹⁴, Maria T Zuber¹⁵
INSTITUTIONS (ALL): 1,4,7,10,11,13 JPL
2. Carnegie Institution of Washington, Washington DC
3, 5 Arizona State University
6. Yale University
8,14,15 MIT
9, 12 Southwest Research Institute
ABSTRACT BODY: Psyche is one of the most singular asteroids in the main belt. It is thought to be the core of a Vesta-sized planetesimal, exposed through collisions. Based on spectra, radar surface properties, and bulk density estimates, it appears to be a world not of ice or silicate rock, but of iron. By understanding its nature, we can glean insights into the differentiation of planetesimals, the growth of planets, the composition and structure of a planetary core, and the geology of a metallic body. For all of these reasons, and its relative accessibility to low cost rendezvous and orbit, Psyche is a superb target for a Discovery-class mission that would measure its geology and geomorphology, shape, composition, magnetic field, and mass distribution.
KEYWORDS: 6205 PLANETARY SCIENCES: SOLAR SYSTEM OBJECTS Asteroids, 6297 PLANETARY SCIENCES: SOLAR SYSTEM OBJECTS Instruments and techniques.
Additional Details
Previously Presented Material: 25% Low Cost Planetary Missions conference 2013
CONTACT (E-MAIL ONLY): [email protected]


A search of the forum revealed this post - where Psyche's been mentioned in a mining context.

Any remote sensing experts here want to weigh in on unique aspects of interrogating instruments that would be desired for such a mission? I don't know if they can do a landing within a discovery class budget.

[Blackstar]

I don't think AGU presentations get posted. But you can always look up the presenter and shoot them an email requesting a copy.

One unfortunate fact is that Discovery's budget has been gutted, so there are going to be fewer mission opportunities for asteroid and comet missions.

[plutogno]

orbiting Psyche was also a part of the INSIDER mission recently proposed to ESA, but not approved. details in this (large) file: http://sci.esa.int/science-e/www/object/doc.cfm?fobjectid=52029

[catdlr]

bump for an update....

Deep Space Communications via Faraway Photons

The Deep Space Optical Communications (DSOC) package aboard NASA's Psyche mission utilizes photons -- the fundamental particle of visible light -- to transmit more data in a given amount of time. The DSOC goal is to increase spacecraft communications performance and efficiency by 10 to 100 times over conventional means, all without increasing the mission burden in mass, volume, power and/or spectrum.

Source: https://www.jpl.nasa.gov/news/news.php?feature=6967

Photo Description and Credit:

This artist's-concept illustration depicts the spacecraft of NASA's Psyche mission near the mission's target, the metal asteroid Psyche. The artwork was created in May 2017 to show the five-panel solar arrays planned for the spacecraft.

The spacecraft's structure will include power and propulsion systems to travel to, and orbit, the asteroid. These systems will combine solar power with electric propulsion to carry the scientific instruments used to study the asteroid through space.

The mission plans launch in 2022 and arrival at Psyche, between the orbits of Mars and Jupiter, in 2026. This selected asteroid is made almost entirely of nickel-iron metal. It offers evidence about violent collisions that created Earth and other terrestrial planets.

[redliox]

I'm still surprised they decided to include optical communication for a mission going out to ~3AU, but as I believe I said before regarding lasercom on Psyche it would definitely test how great a range it could work.  I remember how it was very briefly considered on Europa Clipper (and I think some versions of its predecessors) but it was shot down quickly since it's not perfectly matured, at least not for Jupiter.  Should be interesting since this is the 2nd mission testing a new technology out, much like Deep Space 1 preceded Dawn and now Psyche regarding ion drives.

Eager to hear more news about Psyche, but we do have 5 years before it's due for launch so hardly a rush.

[Proponent]

I'm still surprised they decided to include optical communication for a mission going out to ~3AU

Am I correct in recalling that proposals for Discovery missions now gain points for trying out new technologies?

[Blackstar]

but it was shot down quickly since it's not perfectly matured, at least not for Jupiter.  Should be interesting since this is the 2nd mission testing a new technology out, much like Deep Space 1 preceded Dawn and now Psyche regarding ion drives.

Optical com is an idea that has been around for a very long time--there are proposals going back to 1966 and the Apollo Applications Program. There have been LEO demonstration missions too; NRO flew one in the late 1990s. But it's clearly a tough nut to crack, because it still has not been deployed operationally in deep space, and it's not even in widespread use in LEO.

[redliox]

Optical com is an idea that has been around for a very long time--there are proposals going back to 1966 and the Apollo Applications Program. There have been LEO demonstration missions too; NRO flew one in the late 1990s. But it's clearly a tough nut to crack, because it still has not been deployed operationally in deep space, and it's not even in widespread use in LEO.

Would you agree then that going from testing out in lunar orbit to an asteroid deep in the main belt amounts to a heavy leap?

[Alpha_Centauri]

Before it was killed-off ESA planned to test optical coms on the AIM asteroid misssion, there certainly seems to be the feeling the technology is mature enough to test in deep space. That system was limited, about 0.5 AU range IIRC, but no doubt the US system is a more capable design.

[Blackstar]

Optical com is an idea that has been around for a very long time--there are proposals going back to 1966 and the Apollo Applications Program. There have been LEO demonstration missions too; NRO flew one in the late 1990s. But it's clearly a tough nut to crack, because it still has not been deployed operationally in deep space, and it's not even in widespread use in LEO.

Would you agree then that going from testing out in lunar orbit to an asteroid deep in the main belt amounts to a heavy leap?

Yeah, it's an important development. I just wish that we were at the point where we were now baselining this technology for every planetary spacecraft. But that is clearly a ways off.

[LouScheffer]

...About optical coms...

Yeah, it's an important development. I just wish that we were at the point where we were now baselining this technology for every planetary spacecraft. But that is clearly a ways off.

It's not obvious to me that optical is the right way to go.  Compare instead to beefing up the DSN with a large (10x area of a 35 meter dish) receive-only array at each DSN station. 

1) The RF array allows a 10x science return from any mission, including ones already designed/launched.
2) RF works under more weather conditions.
3) The spacecraft end of the link does not change, so low risk, and you can keep fiddling with the ground end while the craft is in flight.
4) Capability is divisible.  You can get 5x from 2 missions, 3x from 3, and so on.
5) Optical coms does not remove the radio payload from the spacecraft, since it's still needed when attitude is not secure.

[Blackstar]

It's not obvious to me that optical is the right way to go.  Compare instead to beefing up the DSN with a large (10x area of a 35 meter dish) receive-only array at each DSN station. 

I've sat in several briefings about "the future of the DSN" and never heard that idea.

[LouScheffer]

It's not obvious to me that optical is the right way to go.  Compare instead to beefing up the DSN with a large (10x area of a 35 meter dish) receive-only array at each DSN station. 

I've sat in several briefings about "the future of the DSN" and never heard that idea.

About a decade ago, large arrays of smaller antennas was seriously studied.
The DSN Array Development Program
A DSN Array for the 21st Century
Operations concept for array-based deep space network

and they build and verified prototypes:
The 6-meter breadboard antenna for the deep space network large array

But when it came time to spend money, they went conservative and just ordered more of the same.  I'm not sure of the exact reasoning, but I suspect it was some combination of:
(a) A big array requires up-front money, maybe $300 million for all three stations.   You can buy new additional 34m antennas for a $30-40 million, one at a time.
(b) It's hard to make an array do *everything* the DSN does.  Transmitting is harder to phase up.  Lots of medium size phase controllable transmitters is a development project.  It's hard to handle all the bands (S, X, and K).  It's hard to receive while transmitting (for ranging).   The big beam waveguide antennas can do all of these.

I don't know why they did not consider a DSN station to have (say) 2 full service dishes plus a large receive array.  That's what I would have chosen.

[Blackstar]

It's not obvious to me that optical is the right way to go.  Compare instead to beefing up the DSN with a large (10x area of a 35 meter dish) receive-only array at each DSN station. 

I've sat in several briefings about "the future of the DSN" and never heard that idea.

About a decade ago, large arrays of smaller antennas was seriously studied.
The DSN Array Development Program
A DSN Array for the 21st Century
Operations concept for array-based deep space network

and they build and verified prototypes:
The 6-meter breadboard antenna for the deep space network large array

But when it came time to spend money, they went conservative and just ordered more of the same.  I'm not sure of the exact reasoning, but I suspect it was some combination of:
(a) A big array requires up-front money, maybe $300 million for all three stations.   You can buy new additional 34m antennas for a $30-40 million, one at a time.
(b) It's hard to make an array do *everything* the DSN does.  Transmitting is harder to phase up.  Lots of medium size phase controllable transmitters is a development project.  It's hard to handle all the bands (S, X, and K).  It's hard to receive while transmitting (for ranging).   The big beam waveguide antennas can do all of these.

I don't know why they did not consider a DSN station to have (say) 2 full service dishes plus a large receive array.  That's what I would have chosen.

It was about a decade ago that I started sitting in those kinds of briefings. Usually what I heard was some variation of going to the 34-meter dishes and a question about whether/if/when/huh? to retire the 70-meter dishes. I'm no expert on this, but I think that X-band is used for radio science, and that's a capability that you lose at the smaller dishes. Nobody wanted to lose that.

If I remember correctly, the 34-meter dishes they started buying are a kind of sweet spot, because all the equipment is commercially available. Maybe that's why they rejected the big arrays approach, because even though small dishes are commercially available, the integration of an array is custom work. I vaguely remember that the appeal of the 34-meter dishes even included what cranes were needed to assemble them--anything bigger and you need a different and more expensive type of crane for construction.

Wanna see something neat? Look at the current DSN status here:

https://eyes.nasa.gov/dsn/dsn.html

[vjkane]

I think that going to Ka band and more sensitive equipment has allowed the DSN to improve bandwidth while still using the smaller dishes.

I've read that optical allows a 10x improvement or better over expected Ka bandwidths.  The telescopes used for optical are reasonably small and cheap.  Ever larger radio dishes likely are not.

I've also read that pointing accuracy problems limit how far away the spacecraft can be.  I believe the current limit is believed to be somewhere around the distance to Mars plus some.  By going well into the main asteroid belt, Psyche can test the limits.

[ccdengr]

I think that going to Ka band and more sensitive equipment has allowed the DSN to improve bandwidth while still using the smaller dishes.

AFAIK no mission operationally uses Ka band through the DSN.  There are experimental modes available on MRO and Juno and perhaps others, but they're not used for routine ops.

LRO (and SDO?) uses Ka, but only through the ground station at White Sands.

I'll believe in optical when I see it used operationally.

[vjkane]

I think that going to Ka band and more sensitive equipment has allowed the DSN to improve bandwidth while still using the smaller dishes.

AFAIK no mission operationally uses Ka band through the DSN.  There are experimental modes available on MRO and Juno and perhaps others, but they're not used for routine ops.

LRO (and SDO?) uses Ka, but only through the ground station at White Sands.

I'll believe in optical when I see it used operationally.

From the 2014 Discovery AO: "NASA intends to transition all deep-space missions launched after 2016 to the use of Ka-band for science data return (telemetry, tracking, and commanding (TT&C) data may still be transmitted using X-band). In order to better manage the Agency’s transition to Ka-band service, proposed investigations shall baseline the use of Ka-band for science data return."

From the 2016 New Frontiers AO: "NASA intends to transition all space missions to the use of Ka-band for science data return (telemetry, tracking, and commanding (TT&C) data may still be transmitted using X-band or S-band). In order to better manage the Agency’s transition to Ka-band service, proposed investigations are required to baseline the use of Ka-band for science data return, unless it is inappropriate."

[ccdengr]

From the 2014 Discovery AO: "NASA intends..."

"Intends" is not the same thing as actually doing it.  I was merely pointing out how little used Ka has been to date.

[LouScheffer]

I think that going to Ka band and more sensitive equipment has allowed the DSN to improve bandwidth while still using the smaller dishes.

AFAIK no mission operationally uses Ka band through the DSN.  There are experimental modes available on MRO and Juno and perhaps others, but they're not used for routine ops.

Kepler uses K band for data dowlink.  It's a day every three months (or was for the regular mission) since the antenna is fixed so they have to un-science the spacecraft to dowlink.  Uplink and telemetry downlink are X band and do not require pointing.

Some other notes on arrays:
Radio science, in terms of tracking, is indeed best with large single antennas.   Phase centers are well defined and lots of errors cancel out, since the same antenna can receive and transmit at the same time.   But you don't need to track all missions all the time - they take turns now, of necessity.  If you had an additional downlink only capability, missions could downlink science when they are not already tracking (which is most of the time).

The array of small dishes was specified and prototyped to work at both X and K band, so you could get both larger area and higher frequency.  A roughly 3-4x increase for K band (true whatever antenna is used), then another 10x for increased receive area.   That's 30-40x over current science return.

The array approach is (in theory at least) cheaper per square meter than the large dishes.  For example, a 35 meter DSN dish costs something like $35 million.  But an Australian telescope array bulk ordered 12 meter dishes for $300K each, so something like $2.7 million for the same collecting area (9 dishes).   Of course you now need 9 feeds, low noise amplifiers, and coolers, but these are now available commercially (and projects like the Allen Telescope array have experience with arrays of low noise receivers.)

I can see why it's attractive to DSN to duplicate 35m antennas, so any facility can sub for any other at any time.  But once they have a few of these at each site, then I think it would be better to add as much receive capability as possible, rather than expanding the number of full-service dishes.