HIIB and HTV

[SpaceXFanMobius57]

I just watched the sucessful launch oo the HTV on top of the HIIB! Congradualations Japan! It was a beautiful launch! 7 Days until it reaches the iss! Hope all goes well!

Its always a great event when a country gets its own launch capability! I will be watching!

 

[shuttle_guy]

The launch team must be very proud.

Congratulations to the entire team!

 

[cab7150]

This is an historic launch. Japan is a close ally and it is important that we ensure they are close space development partners as well. I hope they develop man rated launch capability in the near future. (by 2020 would be terrific; sooner would be better, but is not realistic).

 

[gunsandrockets]

Incredibly ballsy move by Japan, just think about it.

First flight of the H-IIB launch vehicle,

First flight of the HTV spacecraft,

And it's not a test flight, it's not an experiment or shakedown cruise,

It is an operational mission to deliver cargo to the ISS!

Well done, Japan

 

[aaron38]

But doesn't that make sense, that it would have actual cargo in it? I mean, the cost of the cargo is probably so small compared to the total launch, why launch empty?

That's what I don't understand about SpaceX's Dragon test launch schedule. They have an empty capsule docking with the station. They're not even going to throw in a bag of M&M's or anything?

 

[aphh]

Does anybody know how much behind or ahead of the ISS HTV currently is? I tried to spot it tonight after ISS had gone, but couldn't.

 

[MeteorWayne]

It's actually a bit hard to say, since they have started maneuvering in for rendevous. From what I can tell the epoch of the current orbit listed in Heavens-Above is after the last engine burn so should be accurate until the next burn. From your location aphh, it would be a real challenge because it's in an even lower orbit than the ISS and is about 3 1/2 magnitudes fainter.

Here's the Mission status center at spaceflightnow:

http://www.spaceflightnow.com/h2b/htv1/status.html

"More burns are on tap beginning early Thursday to bring the HTV within about three miles of the station, where the vehicle will commence its final approach around 1529 GMT.

...
Astronaut Nicole Stott will be standing by at the controls of the station's robotic arm, ready to grapple the supply ship as it flies about 30 feet below the complex's Kibo laboratory module.

Current estimates place the grapple time around 1950 GMT Thursday. The HTV will be moved to the Harmony module's downward-facing port for berthing a few hours later"

 

[aphh]

Thanks for the info,

ISS just went by and I couldn't see the HTV. It has to be rather close now, if it's going to be within 3 miles in less than a day. I'm guessing it is just not visible for me.

 

[MeteorWayne]

It's currently a few hundred miles behind, about 4 minutes. Since it is in a lower orbit it is catching up about 40 seconds per orbit (~ 90 minutes). From what I understand it will have another burn early tomorrow moning (GMT)

Edit:
FYI, current ISS orbit is 341 x 353 km, HTV is 305 x 323 km.

ISS orbit is 91.5 minutes, HTV is 90.8 minutes.

 

[MeteorWayne]

OK, the near final orbit adjustment has been made, so the craft are very close in the sky.

The ISS orbit is 341 x 353 km, the HTV has been raised to 328 x 341 km. SO you can see the intersection will occur at ~ 341 km.

FRom spaceflightnow: http://www.spaceflightnow.com/h2b/htv1/status.html

1630 GMT (12:30 p.m. EDT; 1:30 a.m. JST)
Everything seems to be progressing well with the HTV's rendezvous with the space station. JAXA reported the cargo ship departed the approach initiation point 5 kilometers, or 3.1 miles, directly behind the space station about an hour ago.
The HTV should now be arriving at the rendezvous insertion point 500 meters, or 1,640 feet, below the complex. At that point, the spacecraft will switch its navigation system from relative GPS to the laser sensor, which shoots beams of light toward the station for precise range and closing rate information.

"We have a laser head installed on the HTV side which will shoot the laser beam to the reflectors. By measuring the distance and also the angle of the returned signal, we'll know the XYZ position relative to the ISS," said Hiro Uematsu, a senior engineer on the HTV spacecraft.

Space station cameras earlier this morning spotted the HTV as it was flying a a few miles behind the station, appearing as a bright star trailing the complex.

 

[MeteorWayne]

Live NASA TV coverage will start about 1 1/2 hours from now at 3 PM EDT.

 

[MeteorWayne]

HTV has been grappled!!! 2:47 CDT.

 

[scottb50]

HTV has been grappled!!! 2:47 CDT.

I would think you could put a multi piece heat shield and an inflatable envelope in a pretty tight package around one of these containers. Inflate the ballutte and release the heat shield at lower altitudes. You could also take a small, light weight vehicle to orbit, designed for controlled landings with passengers. Release the balloon and heat shield at atmospheric altitudes and moderate speeds, start engines and make a normal landing.

A Falcon 9 would easily carry something in the medium business jet range size, not suggesting modifying one. 10-12 passengers and crew. The available cargo containers just as easily separate and descend on parachutes for subsequent re-use. As a bonus a small parachute should recover the ballute and make the entire system re-usable, with TPS maintenance being the biggest cost.

 

[gunsandrockets]

But doesn't that make sense, that [the HTV] would have actual cargo in it? I mean, the cost of the cargo is probably so small compared to the total launch, why launch empty?

That's what I don't understand about SpaceX's Dragon test launch schedule. They have an empty capsule docking with the station. They're not even going to throw in a bag of M&M's or anything?

The HTV is carrying 5 tons of cargo to the ISS on it's maiden voyage. Timely cargo supply to the ISS is critical to maintaining safe and productive operation of the ISS. The cargo supplied by Japan is also part of the deal made by Japan for participation in the ISS program, as a cost offset for ISS operations.

All of these reasons are why it was a gamble for Japan to launch a functional cargo mission on the very first flight of it's HTV cargo spacecraft. If the mission had failed, there is no easy and quick substitution for the cargo supplied by this flight.

That's also why SpaceX and NASA are conducting multiple test flights of the Falcon 9/Dragon before the first cargo run to the ISS.

 

[aphh]

Japan space engineering is terrific. They made it look easy, as if they had always been in the business of launching tons of cargo to outer-space to rendezvous with a space-station.

Way to go Nippon aerospace!

 

[aphh]

HTV has been grappled!!! 2:47 CDT.

Wasn't the rendezvous similar case to the thread we had a while back here, where we discussed about intersecting orbits? I read they had 99 second window to grab the HTV with the arm at the intersection of the two orbits?

HTV was on slightly lower orbit than the ISS, so HTV was moving faster relative to ISS and hence the two met briefly at the intersecting point of the orbits. Upon grapple HTV's orbital parameters were changed slightly.

But wouldn't this slightly alter the orbit of the ISS aswell? A reaction pair they were.

 

[Zipi]

But wouldn't this slightly alter the orbit of the ISS aswell? A reaction pair they were.

Yes of course. But ISS has that much larger mass that it is meaningless alteration. And of course if they need to correct ISS orbit they can use the thrusters of Progress ship currently docked at the end of the ISS. After Progress soon leaves, then they can use Russian thrusters if needed.

 

[MeteorWayne]

If I remember my orbits right, since they were at the same height (341 km) at that instant they should have been traveling almost exactly the same speed.

The ISS orbit at the time was 353 x 341 km, the HTV 328 x 341. Both are pretty circular.

The average orbital speed for the ISS is 7701.7 m/s, for HTV 7708.9 m/s.

But the ISS, being at perigee would be moving faster, and the HTV being at apogee would be moving slower.

The speed for a circular orbit at 341 km is 7705.1 m/s.

I have to look up the formula for instanateous speed in an elliptical orbit...I looked on the top of my head, and it ain't there

 

[aphh]

If I remember my orbits right, since they were at the same height (341 km) at that instant they should have been traveling almost exactly the same speed.

Same speed, but since the orbits weren't exactly the same, slightly different directions. 99 second window before drifting apart. HTV's direction put a tiny load on the ISS via the arm, but as mentioned above, practically negligible and easily compensated.

This is how you rendezvous in space.

 

[TC_sc]

If I remember my orbits right, since they were at the same height (341 km) at that instant they should have been traveling almost exactly the same speed.

Same speed, but since the orbits weren't exactly the same, slightly different directions. 99 second window before drifting apart. HTV's direction put a tiny load on the ISS via the arm, but as mentioned above, practically negligible and easily compensated.

This is how you rendezvous in space.

I wondered myself why just a 99 sec. window. I did read that they had remote control of the HTV and could have used thrusters to have another chance. I guess due to contamination of the experiment platform that was a choice of last resort.

 

[Delphinus100]

But doesn't that make sense, that it would have actual cargo in it? I mean, the cost of the cargo is probably so small compared to the total launch, why launch empty?

That's what I don't understand about SpaceX's Dragon test launch schedule. They have an empty capsule docking with the station. They're not even going to throw in a bag of M&M's or anything?

It appears SpaceX will launch a Dragon on its first flight, but there's nothing about it going to ISS at all.

http://www.hobbyspace.com/nucleus/index ... emid=15427

 

[mjbernier]

It looks like SpaceX is going to fly a "qualification" version of Dragon on its first F9 flight. I suppose that's the modern version of what used to be called a "boilerplate" model of a vehicle? Or is this more advanced? I would hope it's advanced enough to test all the major Dragon systems, including on-orbit maneuvers, re-entry/splashdown, and capsule recovery. That would be a big step toward building confidence with NASA going into the C1 and C2 flights, and perhaps the C2 flight could then carry a useful "live" payload to the ISS rather than an inert "dummy" payload.

 

[aphh]

I wondered myself why just a 99 sec. window. I did read that they had remote control of the HTV and could have used thrusters to have another chance. I guess due to contamination of the experiment platform that was a choice of last resort.

I don't know about the details, but since this was a maiden flight of a new spacecraft, it may have been that using thrusters in the vicinity of ISS was not allowed.

Had the grapple procedure not worked out the first time, HTV probably would have needed to fly away from ISS before attempting to close in on it again. Somebody else might know whether the fuel carried by HTV would have allowed multiple attempts at approaching the station.

 

[shuttle_guy]

I wondered myself why just a 99 sec. window. I did read that they had remote control of the HTV and could have used thrusters to have another chance. I guess due to contamination of the experiment platform that was a choice of last resort.

I don't know about the details, but since this was a maiden flight of a new spacecraft, it may have been that using thrusters in the vicinity of ISS was not allowed.

Had the grapple procedure not worked out the first time, HTV probably would have needed to fly away from ISS before attempting to close in on it again. Somebody else might know whether the fuel carried by HTV would have allowed multiple attempts at approaching the station.

The short window for grapple is standard ops. This is, as mentioned before here, orbital mechanic influences and residual attitude rates build up with time. For the grapple both the ISS and the HTV are in free drift so their thrusters to not fire to correct any rates.

 

[TC_sc]

I wondered myself why just a 99 sec. window. I did read that they had remote control of the HTV and could have used thrusters to have another chance. I guess due to contamination of the experiment platform that was a choice of last resort.

I don't know about the details, but since this was a maiden flight of a new spacecraft, it may have been that using thrusters in the vicinity of ISS was not allowed.

Had the grapple procedure not worked out the first time, HTV probably would have needed to fly away from ISS before attempting to close in on it again. Somebody else might know whether the fuel carried by HTV would have allowed multiple attempts at approaching the station.

The short window for grapple is standard ops. This is, as mentioned before here, orbital mechanics and residual attitude rates build up with time. For the grapple both the ISS and the HTV are in free drift so their thrusters to not fire to correct any rates.

I am sure I read here at SDC that they wanted the HTV to be close to the JAXA experimental platform and because of possible contamination to the experiments they didn't want to have to fire thrusters. If they had missed in that 99 second window they would have used the HTV thrusters to get a second chance. I think the article just said they had contingencies. The shuttle does dock near the same location so I might have to wonder about that. Maybe we can have whoever wrote the HTV articles to fill us in.