# NASA finds India's missing lunar orbiter with Earth-bound radar

In 2009, a lunar orbiter launched by India went quiet and was never heard from again. Fast-forward eight years and NASA say it's spotted it using an Earth-based radar. The Indian Space Research Organisation's Chandrayaan-1 orbiter was supposed to spend two years on its mission, but after 312 days its communications systems …

1. #### Puzzled

If they thought it would be 200km above the surface, why did they aim the illuminating radar at a point 160km above the pole?

1. #### Re: Puzzled

So it covered a fairly large part of the expected arc, not the very tip.

My ASCII-art is terrible, but think on a circle and draw a line.

If the line is a true tangent (touches the very edge) to the circle you get one moment, and if you miss a little high you never see anything at all.

If the line crosses slightly inside, you get two chances and if you miss a little high you still see something.

2. #### Re: Puzzled

You do realize that the US and other governments routinely track space debris and objects in space, right?

I don't know how small they can track, that's classified. As to covering the north pole, that would be one of the first and most heavily monitored space.

If you can't guess, use your imagination.

1. #### Re: Puzzled

@AC

And what relevance does any of what you said, have to the (quite sensible imho) question asked?

1. #### Re: Puzzled

AC is confusing North Pole of the Moon with that of the Earth ;)

2. #### Re: Puzzled

Anonymous Coward, why would the North pole of the moon be heavily monitored? What secrets does it hold? Or are you just confusing the Lunar North pole with the Earth's North Pole? It's obvious why NASA (ie the USA) would want to monitor the Earth's North Pole, but not so obvious why the interest in the Moon's north pole (other than to track the Indian Lunar orbiter).

2. So the spacecraft passes through the beam. I'm not sure how well focussed NASA can keep the beam after travelling 385,000 km. 160km probably means they can just miss the Moon and consequently remove any backscatter from the surface. They should still spot anything orbitting at 200km above the poles, especially when the craft's orbit is end on to the Earth so it will rise and fall through the aim point of the beam.

3. #### In 2009, a lunar orbiter launched by India went quiet and never heard from again.

India loses orbiter, The Register loses verb ?

1. #### Re: In 2009, a lunar orbiter launched by India went quiet and never heard from again.

India accidentally their orbiter?

In other news: the Pope is Catholic, and copy-editing of English-language news Web sites is appalling…

4. #### Need unattended Moon base

With giant optical and radio telescopes. Maybe on far side so shielded from Earth interference and maybe one on either pole.

You'd need a very big array to reach Mars.

I'm looking forward to "James Web" space scope. I hope the launch and deployment is OK.

1. #### Re: Need unattended Moon base

We had one. Back in 1999.

The problem is that it led to the loss of the moon when the nuclear waste dump it was built to manage went boom and sent the moon out of orbit.

NASA quietly replaced the real moon with a dummy one so no one would notice, but the one you see now is just a flat disc, so there is no base on it.

1. #### Re: Need unattended Moon base

It wasn't an incident, it was planned. It was a cunning plan to get rid of bad, dull actors who stubbornly kept adopting 1970s ugly fashion till the end of the XX century...

5. #### Mascons

"As NASA explains, it couldn't simply extrapolate the little orbiter's last-known orbit because the moon is “riddled with mascons (regions with higher-than-average gravitational pull) that can dramatically affect a spacecraft's orbit over time”."

NICE!! I learned some new physics this morning :-) Thank you El Reg!

1. #### Re: Mascons

What about Tycho Crater? Any anomalous magnetic fields there?

2. #### Re: Mascons

"higher-than-average gravitational pull"

That would be "gravitational waves" by another name!

6. its more todo with building my navigation system using topology radar to scan for space debris with omni directional pings, and generate 3d models in the 3d star map to be used in the next gen space shuttle

so they would want elite dangerous engine without the game assets, just the 160,000 real time stars from our own galaxy https://www.elitedangerous.com/ - then link up your gyroscopes, and thrust math for 1:1 real time positioning of your craft in space, with a procedurally drawn galaxy stored on DNA and just update the renderer until holograms come along

1. whats with the thumbs down, its the only way to navigate space, especially if you want to go 256 million MPH with my EM pulse propulsion thrusters, BAE Systems probably have working in fighter jets https://youtu.be/NMMA5KgIvYE?t=2m19s with 0.05 second accerlation to reach 256 million MPH with some megawatt magnets and the repelling force

1. probably whats powering the mystery plane https://www.youtube.com/watch?v=HiFIw8OkTWk

need ait to cool the magnets or you end up with plasma

2. #### @ Zmodem

Don't forget, you'll need some megagausshour Lithium Ion batteries to power those magnets!

May the repelling force be with you ....

>> For the batteries

1. #### Re: @ Zmodem

doubt it, a maglev train uses around 8000Kw to move along at 400mph, and so does the french TGV train, so a jet fighter like BAE, would need less then 0.2MW reactor, and that would still be overkill if you want mach 4, and had a nanotube superconducting forcefield and decent radar system with super computer onboard

and fly from the ground and into space without the need for air for combustion which is'nt happening, and use a power charge to shoot off, or just fly around the world non stop for 10 years at mach 4

1. #### Re: @ Zmodem

if they have em thrusters working, they will just fly around for 30 years like ameria and the tr3b and leave skylon to have reaction engines if they dont fail in 2020

7. #### "dodging debris or asteroids should be easier"

I suspect getting the planet to dodge an asteroid might be a little harder than you might think.

8. #### Olympus Control to Maven N34456D

- Be advised we have heavy local traffic and an inbound near your position. Make an immediate right turn to bearing Two Three Zero and descend to one million two hundred thousand feet.

9. #### MMM. Space 1999 or UFO?

Ok, so maybe I'm aging myself because I remember watching these shows when I was a kid.

Too bad I didn't save my models and lunch box from Space 1999. Or Lance Link for that matter.

1. #### Re: MMM. Space 1999 or UFO?

Ah yes, A computerised satellite called SID was responsible IIRC.

10. #### Doppler?

It would be interesting to know if they determined the orbital speed of the craft by using the doppler shift of the returned signal. Of course, to do that, they'd have to factor in the ground motion of the transmitting and receiving stations, as well as the motion of the Moon (libration and other).

Dave

P.S. I'll get my coat. It's the one with the radar detector in the pocket.

11. #### This is pretty amazing.

A target a few metres across has been found in a circle roughly 100Km in diameter after having had been subjected to unknown gravity forces for 8 years.

From a distance of about 1 light second.

Sadly it looks like they never did deploy the gravity gradiometer Dr Forward invented

12. #### Orbital parameters?

Does anyone know what orbital inclination the satellite used? Without very careful selection, lunar satellites tend to wander rapidly and perform unscheduled lithobraking maneuvers. Even "stable" lunar orbits are subject to a lot of perturbation.

13. #### "KNowing where to look"

"As a proof-of-concept, the mission scientists had previously used the radar technique to spot NASA's Lunar Reconnaissance Orbiter, a much easier task since that craft's navigators knew precisely where to look."

They still knew more or less where to look, just needing to open up the observation window time for longer.

Looking for unknown unknowns (asteroids) is somewhat harder, which is why we tend to only see them after they've been past and are brightly illuminated by the sun on the way out. (The ones brightly illuminated by the sun on the way in are - of course - relatively easy to see)

Bear in mind that you don't need to have something actually lithobrake to have a really bad day. A series of large bolide airbursts (eg, a disintegrating comet) is arguably worse and has been postulated as having effectively sterilised a large swathe of North America and kickstarted the Younger Dryas period.

1. #### Re: "KNowing where to look"

they just arnt doing it right, when most are made from iron and not stealth material, asteriods would be easy to pick up with the right setup

if you design a ship right with curves, you just need 2 demi domes center top and bottom, instead of a big ball like a apache helicoptor and other planes

14. #### Lost property

As it's worth more than 50p I hope NASA will do the right thing and report this lost property to the nearest police station?

1. #### Re: Lost property

they nuked the one on the dark side of the moon a few years ago

1. #### Re: Lost property

so now you find them all having a party at rudloe manor and salisbury plain every weekend in the underground city that goes from 1 to the other

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