Nancy Grace Roman Space Telescope

111 pointsposted 8 hours ago
by JumpCrisscross
(science.nasa.gov)

47 Comments

marze

7 hours ago

For some tasks, surveys in particular, field of view is critical. You would need many Hubble telescopes to do what Roman can do mapping everything out there.

"What really makes Roman stand out is that it is designed for wide-field imaging. The cameras on telescopes can often only detect objects in a very small patch of sky. If we use the size that the full moon appears in the sky as our guide, Hubble’s field of view is often smaller than that —meaning each picture it takes is of a patch of sky smaller than the full moon. Webb’s instruments often are even smaller than Hubble’s. Each picture taken by Roman, however, will be larger than the full moon, allowing it to survey more of the sky much faster than Hubble or Webb."

https://science.psu.edu/news/ask-expert-will-roman-help-reve...

SoftTalker

7 hours ago

And yet the narrow-field Hubble produced this famous image

https://science.nasa.gov/mission/hubble/science/universe-unc...

Those are galaxies. In a field of view "about 1/13th the diameter of the full Moon."

drfloyd51

6 hours ago

Your point being?

Hubble in certain circumstances can see narrow and far. If you express this as a cone, you can extrapolate a volume.

It might be very useful to have something that can search wide and maybe not as far; nearer Earth dangers perhaps. Express that as a wider cone and extrapolate volume.

mrkpdl

5 hours ago

I think their point is that it’s amazing.

willis936

6 hours ago

Part of the story is everyone being shocked at being under budget and ahead of schedule. I don't know everything, but I think this is reasonably attributable to the fact that this is a retrofit of an obsolete spy satellite. The leftovers of the security sector will be the most advanced scientific space surveyor. I have to wonder what things would look like with different priorities.

ChocolateGod

6 hours ago

IIRC the mirror is from a spy satellite, but the chassis and electronics are all NASA.

mturmon

43 minutes ago

This is true. The telescope is much more than just the primary mirror.

Roman has two science instruments, a wide-field imager (“WFI”) and a coronagraph (“CGI”) and they were both built by NASA for this purpose (optics, electronics, detectors, deformable mirrors).

The WFI optics includes filters and a prism and grism for spectroscopy, and of course the very large CCD arrays.

The coronagraph is a rather special tech demo and allows imaging of exoplanets (Jupiter-like) while blocking the light of the host star. (https://science.nasa.gov/mission/roman-space-telescope/coron...). It’s a precursor to HWO which is mentioned down-thread.

dylan604

4 hours ago

Isn't that also how Hubble started? I'd assume there's a lot of lessons learned to avoid costly research on conversion of the platform.

_djo_

3 hours ago

No, Hubble didn't reuse any components from spy satellites. However, the chosen mirror diameter was decided by the size of the mirrors being produced for the Keyhole programme, as it meant NASA would be able to reuse Perkin-Elmer's existing fabrication facility.

Mawr

4 hours ago

> I have to wonder what things would look like with different priorities.

Things aren't as simple as more money = more good.

Rapid progress requires adversity, the kind you'll find when nations compete for military power, for example.

dfxm12

6 hours ago

People shouldn't be shocked that employees of the US government can deliver things ahead of schedule and under budget.

The problems are that anyone gave Musk/doge the time of day and that we're too used to the president giving no bid contacts to incompetent donors.

ChocolateGod

4 hours ago

Musks company provides not only the most cost effective but also the most reliable access to space that is currently unparalleled by any other company.

We should thank the government for spending tax money efficiently.

You should blame the legacy aerospace companies whom purposely inflate contracts and take forever to do things for there being a lack of competition, not Musk.

Morromist

3 hours ago

As I see it Musk is lobbying the goverment to give him money to do useless stuff & expensive in space like land on the moon again - basically redirecting funds away from useful stuff like the James Webb Telescope for publicity stunts. Not any different from the legacy aerospace companies, who also lobbied like crazy, except on a bigger, dumber scale.

ChocolateGod

2 hours ago

Starship is mostly funded by Starlink.

Yes, Musk is a crappy character, but that's not a reason to make things up. This isn't Reddit.

Morromist

2 hours ago

Starship isn't actually operational. I'll let you look at their plans for it and you can tell me if they involve doing things the goverment would pay for like landing on the moon and building space stations or not.

dotancohen

2 hours ago

Then you see it wrong. Plans for returning humans to the surface of the moon have been being developed for longer than you've known Musk's name.

The Artemis program was developed out of the Constellation program, which was initiated sometime around 2005 or 6.

Morromist

2 hours ago

How is landing on the moon not a publicity stunt? What can the humans do that massively cheaper robots couldn't - besides take some awesome photos and bring back some more moon rocks?

Of course there have long been plans to go back to the moon because its a cool fun thing to do and whoever happens to be president would likely be well remembered for taking credit for it. That doesn't give it credibility as a useful endeavor.

ChocolateGod

2 hours ago

> How is landing on the moon not a publicity stunt? What can the humans do that massively cheaper robots couldn't - besides take some awesome photos and bring back some more moon rocks?

Humans have intuition and curiosity, they can spot something quickly in the distance that looks peculiar, go to it and quickly inspect it.

ralfd

an hour ago

Even if it is a publicity stunt it was not lobbied by Elon Musk. Also Jeff Bezos Blue Origin got more money for the Artemis program.

Morromist

33 minutes ago

I see. And how do you you know that elon, a notably close supporter of the president didn't have anything to do with the Artemis program? I notice that Chinese electric vehicles are essentially banned in the US, but probably that had nothing to do with Elon as well right? And what does it matter if Blue Origin also made money on the Artemis program?

jryle70

6 hours ago

> the president giving no bid contacts to incompetent donors

Are you talking about SLS?

Oh maybe you'd say that is "Senate Launch System", it's complicated, job program, 50 states sharing, and so on?

dylan604

4 hours ago

I'm really excited about observations we're about to see over the next decade. Bringing NGR online and combining with Rubin, Hubble, and JWST will give us imagery and hopefully new discoveries and understanding.

I had the fortune of letting some of my neighbors through a telescope for the first time for the partial lunar eclipse. I say fortune, because it is amazing to be a part of someone having that experience that never disappoints. Even if they've seen images from NASA/ESA, putting your eyeball directly to the 'scope is much more meaningful.

BoredomIsFun

7 hours ago

Thankfully, it is not Nancy Ann Grace.

y-curious

6 hours ago

The telescope will be used to film sensationalist TV about missing kids

hyperhello

4 hours ago

It watches the stars for evidence of guilt.

danilor

5 hours ago

I'm wondering what are the considerations for having multiple detectors instead of a single large one! Does anybody have an idea? is it just because it's easier?

Starman_Jones

3 hours ago

The primary detector is the wide-field instrument, which, believe it or not, takes pictures with a wide field of view. The secondary detector is the coronagraph instrument, which uses a bunch of funky filters to block out the light from the star to see the halo around it.

Edit: These are the detectors, which are the cameras. There is only one mirror assembly (with two mirrors) that focuses light into these instruments.

ck2

7 hours ago

I'm still holding my breath on this one, will be most amazing telescope in my lifetime

parked in L2 a million miles away with 500mbps data transfer rate (1.5TB per DAY)

we've made it past DOGE destroying it

we've made it past him renaming it after himself and putting his mugshot on it

but Musk still needs to send it out of orbit without explosions, so here's hoping

(Falcon Heavy, don't tell me the odds)

* https://nextspaceflight.com/launches/details/6983/

* JWST vs Roman comparison https://svs.gsfc.nasa.gov/14942/

* https://www.wired.com/story/nasas-nancy-grace-roman-space-te...

* https://www.scientificamerican.com/article/nasas-roman-space...

* https://www.npr.org/2026/08/28/nx-s1-5905370/nasa-nancy-grac...

did not know and it's horrific Roman started as a billion dollar spy satellite sitting in a warehouse unused, but okay we got the crumbs from $20 Trillion in military spending I guess

oh and while the smallest planet Roman can image will be Jupiter-sized, Roman's successor would be able to image earth-like planets

except The Habitale Worlds Observatory Space Telescope HWO was scheduled for 2040 and now will not happen in my lifetime because DOGE got that one, Congress awarded it $150 Million and DOGE changed it to $5 Million

* https://science.nasa.gov/astrophysics/programs/habitable-wor...

* https://en.wikipedia.org/wiki/Habitable_Worlds_Observatory

dylan604

3 hours ago

> * https://nextspaceflight.com/launches/details/6983/

06:25 AM Window Open

06:26 AM Window Close

Is it really just a 1 minute launch window? That seems incredibly tight. If there's any hitch in the countdown, that would pretty much mean a scrubbed launch. Not being well versed in orbital mechanics, why would the window be so short?

Polizeiposaune

an hour ago

Not unusual, and there are likely a number of contributing factors.

Falcon launches to the ISS typically have an instantaneous launch window (roughly, when the plane of the ISS's orbit sweeps over the launch site). If they miss it, they try again about a day later.

Falcon (both Heavy and its little sibling Falcon 9) uses subcooled densified propellants which limit how long it can sit waiting for launch while fueled before the LOX warms and expands too much.

A short window means they only have to compute and verify and program one trajectory.

walrus01

7 hours ago

Is it really 500 Mbps of data headed to Earth 24x7? I'd be very interested to see any available public info about the earth station infrastructure being set up for that.

pjscott

2 hours ago

> but Musk still needs to send it out of orbit without explosions, so here's hoping

The Falcon Heavy has made 12 launches and all of them have been successful. It's built using the same engines as the Falcon 9, which has become the boringly reliable workhorse of space launch, and the rocket cores are very similar in design. I'd bet on a successful launch, and probably on a successful landing of the side boosters.

(Do we really need to politicize launch vehicles, of all things?)

consumer451

7 hours ago

> except The Habitale Worlds Observatory Space Telescope HWO was scheduled for 2040 and now will not happen in my lifetime because DOGE got that one, Congress awarded it $150 Million and DOGE changed it to $5 Million

I was so excited for this. It was the one thing I really wanted to see happen in my own lifetime.

What a deeply moronic waste.

ourmandave

5 hours ago

That's like Hubble funding cuts back in the '70s.

The NASA budget was $5M as a placeholder, but Noel Hinners cut it to zero to light a fire under the community, instead of a bogus pretend-its-still-happening number.

https://en.wikipedia.org/wiki/Hubble_Space_Telescope#Quest_f...

ck2

5 hours ago

yeah but we don't recover from this one like the 70s

the illegal Iran War costs over $120 BILLION, has used over 1000 Tomahawks at $4 Million each (and 1250 patriot missiles)

a BILLION was stolen from nuclear missile maintenance fund for QatarForceOne

another BILLION was stolen for all the DC renovations so far that no-one asked for

billion diverted to his fake "peace board"

so there is money for war and drapes and gold statues but not science that benefits the world

hell he spends $2 MILLION EVERY WEEKEND for GOLF, first term and this term, half billion before he is gone

we could have had people on Mars for all that (not even a project I support but still would be worthy science)

ButlerianJihad

7 hours ago

It is not 500mbps but 500Mbps. https://science.nasa.gov/mission/roman-space-telescope/commu...

"mbps" is a meaningless abbreviation. You need to consistently and correctly use capital letters when communicating technical terms. You cannot "e e cummings" your way into effective writing.

500 megabits per second works out to 5.4 terabytes per day. No idea where you get 1.5, unless you were thinking of 500Mb/hour!

60 × 60 × 24 × 500 × 1000000 ÷ 8

ck2

6 hours ago

my brain is not what it used to be due to long-covid so it's very possible I made a mistake

but 500 megabits per second to me is 500mbps?

ie. my cablemodem is 100mbps which is 100 megabits per second?

and that would [make Roman] 5.4 Terrabytes aka 5.4TB per day

but the transmitter is not at full speed full power 24/7

so it is 1.5TB per day in documentation that I do not have handy but vaguely remember

to repeat the more amazing part is that is from a MILLION MILES away, wow

(JWST "only" does 23mbps, 23 megabits per second)

Sharlin

6 hours ago

The GP is alluding to the fact that the prefix "m" means milli-, not mega-. But that's pointless pedantry. Nobody would ever think that you meant 0.5 bits per second, and bit isn't a SI unit anyway.

ButlerianJihad

6 hours ago

No, your cable modem would be 1.08 terabytes per day.

Does it stop making sense when your calculations for the Roman telescope indicate slower speeds than your connection, which you say is 1/5th the speed?

Now, since the Roman telescope will be at an L2 point, signal acquisition will always be subject to the Earth's rotation. So there will be multiple ground stations involved across the globe.

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

If the quoted rate by NASA of 1.5 terabytes per day is accurate, then it will not be downlinking 24/7, but in bursts. 500Mbps is also the max, where the actual range will be 250-500. We'll need to account for RFI and packet loss, etc.

Mistletoe

6 hours ago

I was scared for a second that the current clown administration had named a space telescope after Nancy Grace the tv personality.

macintux

5 hours ago

I suppose we should be grateful he didn’t force his own name at the last minute. I suppose he still has time.

lokibumdo

3 hours ago

Like Obamacare?

gjm11

3 hours ago

Very unlike Obamacare, which so far as I can make out was mostly a name given to the thing by its (and Obama's) opponents.

Jtsummers

an hour ago

Is this a joke or just a demonstration of ignorance? The name Obamacare was not given to it by Obama, but by opponents of the law. The Obama administration just leaned into it. Blame conservatives if the name bothers you, not Obama and his administration from the time.