Blog | Fiona A. Harrison

What's up October 22?

Tue, 23 Oct 2012 14:37:21 -0700

NuSTAR continues to do well - our first official image release came out. It shows the giant flare from the Galactic center black hole, Sgr A*. NuSTAR got lucky and caught it on the first night we looked at the GC. Just last week we got lucky again, and saw another big one - this time at the same time the Chandra observatory was looking. What will be interesting is to look at the distribution of X-ray energies, especially above energies of 10keV, where no telescope has been senstive enough to isolate the emission from Sgr A* itself.

What's up September 19?

Wed, 19 Sep 2012 08:53:24 -0700

NuSTAR continues to do well. Right now we're pointing at a neutron star called Hercules X-1. Neutron stars have masses somewhat larger than our Sun, but are as compact as San Francisco. A teaspoon weighs as much as all the humans on Earth. These objects also have very intense magnetic fields. When they are in a binary system with a "normal" star matter can be transferred from the star to the neutron star. The huge magnetic fields create distortions in the spectrum (or rainbow) of X-rays that result, and NuSTAR will study this distorted spectrum to understand the physics taking place in these systems.

In other news - want to catch up in person? We're hosting a google+ event to roll out the KQED (Bay Area public television) show on black holes, highlighting NuSTAR.

Add KQED Science to your circle and you'll find the event.

What's up Aug 30?

Thu, 30 Aug 2012 22:45:05 -0700

NuSTAR is finally really in science mode - we're planning the observations for the whole month of September. Its an exciting month. We'll be looking at a nearby "starburst galaxy" - or a galaxy that is forming stars at an amazing rate - much greater than our Milky Way. The rate of star formation is so great for a galaxy undergoing a starburst that, if the rate was sustained, the gas reservoirs from which stars are formed would be used up on timescales much shorter than the age of the galaxy. So, these special galaxies must have something in their recent past that triggers this amazing rate of star formation. A consequence of forming a lot of stars is that you end up with a lot of black holes and neutron stars, which are the endpoints of massive star formation. These objects shine in the X-ray band, and in particular extending sensitivity to the high energy X-ray band can tell us about the composition of the population of compact objects (black holes vs. neutron stars) which is interesting for understanding the ratio of high to low mass star formation.

What's up August 25

Sat, 25 Aug 2012 20:14:09 -0700

NuSTAR continues to look at the Cassiopeia A supernova remnant through tonight. Then, we slew to pick up a simultaneous observation with Chandra of an ultraluminous infrared galaxy, to help answer the question of whether a central black hole or star formation power these galaxies. Then, back to a new position on Cas A. We plan to post an image of the supernova remnant taken with NuSTAR soon.

What's up August 19?

Sun, 19 Aug 2012 21:22:57 -0700

Right now NuSTAR is looking at a famous remnant of a supernova explosion in the constellaton Cassiopeia. The remnant, called "Cas A" is the brightest extrasolar radio source in the sky. The supernova occurred approximately 11,000 light-years (3.4 kpc) away in the Milky Way.The expanding cloud of material left over from the supernova is now approximately 10 light-years (3 pc) across. Despite its radio brilliance, however, it is extremely faint optically, and is only visible on long-exposure photographs.

NuSTAR's high energy X-ray image will trace the distribution of radioactive elements in this remnant, telling us about the explosive dynamics in the core of the supernova.

The NuSTAR team is working hard to interpret the data taken during calibration of the observatory so that the data from this science observation can be used to understand the absolute brilliance of this object in the high energy X-ray region of the spectrum.

What's up August 8

Wed, 08 Aug 2012 23:12:17 -0700

Its been a long time since the last blog entry. This is largely because the mission moved from 'transformative' events like mast deployment to 'the devil is in the details'.

Currently the NuSTAR team is occupied with understanding how sensitive the telescope will be accross the spectrum of high energy X-rays, and also how crisp the images will be. It is clear we built really nice optics and detectors, and our current challenge is how do we accurately remove motion of the large 10-m structure and not blur the images. The ability is there but there is some software development to do. If you want an analogy - suppose you snapped a picture with your cell phone camera, but your hand was unsteady so you get a blurred image. But, if you had the camera in 'video mode' you could capture many crisp frames that show the motion, then shift and add them to make one clear picture. This is what NuSTAR is doing - how do we 'shift and add'? We measure the instantaneous position of the optics relative to the detectors 16 times/section and we correct each X-ray we detect based on these measurements.

What's up July 16?

Mon, 16 Jul 2012 14:39:03 -0700

A fun day for NuSTAR - 3C 273 has been simultaneously observed by NuSTAR, XMM, Swift, Suzaku, and INTEGRAL! This will be our primary cross calibration for joint observations.

NuSTAR will stay on 3C 273 until the end of the week (Thursday), completing a ~300 ksec observation that will be used both for calibration and by the AGN physics group for constraining coronal temperature. After that, NuSTAR will do a quick pointing offset maneuver using 1E1740 before beginning a joint Chandra/NuSTAR/Keck observation of Sgr A* (beginning Friday). After that, NuSTAR will do a set of calibrations on the Crab prior to beginning a joint observation of NGC 1365 with XMM.

Longer term, NuSTAR will return to calibration observations, with 3 days of "down time" the week of August 6 to install some SC code patches and test the safe hold.

What's up July 6?

Fri, 06 Jul 2012 14:49:10 -0700

In the last week NuSTAR has been performing a series of alignment measurements - pointing all over the sky at different bright X-ray sources to check the alignment of the spacecraft and telescope systems. This will take through the weekend. Next week these data will be used to possibly update the telescope alignment again, after which point spread function calibrations will begin.

All systems remain nominal.

What's up July 1?

Sun, 01 Jul 2012 21:37:18 -0700

Today the NuSTAR team adjusted the alignment of the X-ray optics relative to the detectors using a mechanism that can 'tip', 'tilt' and rotate the alignment. The information fo rhow to do this adjustment was gathered by looking at a supermassive black hole called 3C 273.

All systems are still nominal, and the observatory prepares to point all over the sky to test out the attitude determination system in preparation for science operations.

What's up June 26?

Tue, 26 Jun 2012 20:51:24 -0700

We went to a worst-case attitude in terms of disturbance torques today and the spacecraft handled it very well with good pointing performance. We also worked out misalignments between the instrument star tracker and the SC star trackers in preparation for first-light on Thursday (Cyg X-1 in case you hadn't heard). The instrument team continues to pour over the data to analyze background and tune up the shields and detectors for science operations.

Bill Craig, the Caltech crew - esp Kristin, Karl, Brian, the ACS Orbital team, the whole UCB Ops team (Manfred, Mark, Bryce & co) and JPL systems engineering teams (Jason and Byron) in particular deserve all our thanks for a job very well done. It is reminiscent of having a child - birth is over quickly, sleep deprivation continues for weeks.....at least...

Sunday June 24

Sun, 24 Jun 2012 13:59:19 -0700

Everything continues to go very well. Yesterday we successfully aligned the laser metrology system using the mast adjustment mechanism so that the lasers are close to the centers of the metrology detectors. Kudos to Bill Craig for getting the alignment correct (not an easy job) and to the Caltech team for their quick and expert analysis correction calculating the required adjustment. Kristin also has analyzed the mast motion and determined that the model expectations for the motion are dead on.

We also turned the anticoincidence shields on yesterday, and took data to validate that they are functioning properly. Today we turned the CZT detectors on, and they are functioning nominally. Overnight we'll took our first real background data. Analysis ongoing.

What's up June 21

Thu, 21 Jun 2012 21:46:07 -0700

Successful mast deploy, and equally important SC is under control having gone from one very different inertia state to another. Perhaps as or more challenging than the launch. After tomorrow, we will have a functioning science instrument (!!!)

Go NuSTAR!

What is up June 20?

Wed, 20 Jun 2012 17:01:07 -0700

Today was another good day for NuSTAR. We released two sets of actuators that hold the two benches (optics and focal plane) together, and we released the aperture stops (that block the diffuse background - they will deploy with the mast), so NuSTAR is poised for mast deployment tomorrow.

All systems are nominal.

What's up June 19?

Tue, 19 Jun 2012 10:53:22 -0700

Its been a productive few days. Some minor tweaking needs to be done with the star trackers, but we just turned the instrument processors, heaters and laser metrology system on, and all looks good! The spacecraft is pointing in normal mode with the star trackers in the loop. So far so good, Mast deploys on Thursday.

What's up June 15?

Fri, 15 Jun 2012 12:44:37 -0700

The NuSTAR Observatory is healthy and all systems are in a nominal state. Having tons of fun with the star trackers. Imaging clouds, floating debris still surrounding the SC (which will dissipate soon we expect) but the trackers are working well. The momentum management issue is behind us. Current plan is still to get to mast deploy on Wednesday instead of Tuesday with a mandatory Sunday crew rest day.

What's up June 14

Thu, 14 Jun 2012 20:08:14 -0700

What's up June 14

The last couple of days have been more interesting than planned. After a successful launch, the NuSTAR satellite reoriented to position its deployed solar arrays toward the sun and entered a stable sun pointing mode as planned using its coarse sun sensors and reaction wheels. The spacecraft changes orientation by changing the speed at which the reaction wheels spin. The spacecraft power systems indicated excellent performance with over 23 Amps of current from the arrays and the batteries were fully charged. Thermal, radio communications and Command and Data Handling subsystems were nominal and the spacecraft bus commissioning process, expected to take one week, began as planned.

Shortly after NuSTAR started to use its attitude control system, which employs a combination of reaction wheels and magnetic torque bars to maintain spacecraft pointing, the engineering team noticed that the reaction wheels started to spin faster than needed to maintain its proper orientation. This was not expected, because the magnetic torquer bars are controlled by the spacecraft software to create a magnetic field that torques against Earth’s field. This enables a low reaction wheel speed to be maintained. The NuSTAR team temporarily disabled the torque bars, and the spacecraft continued to point using the reaction wheels alone. The cause of this issue was traced to a bad calibration on the magnetometer and a phasing error with the torque bars. These were corrected, and attitude control was reenabled. Momentum management is back in control and the attitude control is funcitoning as expected. With this behind us we will continue as planned bringing up the spacecraft to a state good for mast deployment next week.

What's up June 13 - launch day?

Wed, 13 Jun 2012 07:50:38 -0700

At the Mission Ops Center - second shift completed the S/C and instrument check out around midnight. Came in at 3am to start voice checks with Kwaj. A glitch in one of the receivers caused a data review and eventually a 30 minute launch delay - all looks good now.

7:50 am - the L1011 started taxi.

8:01 am Pacific the L1011 took off.

9:00 am Pacific - Near picture perfect launch.

9:39 am confirmed solar array deployment, communications and S/C is under control

What's up June 12?

Tue, 12 Jun 2012 12:37:45 -0700

Everything is still go for launch tomorrow. Here at mission control people are just hanging out, taking care of last minute details. Its supposed to be a "crew rest" day, but people are wound up enough not many of us are actually resting. But, its hard to concentrate. "First shift" gets here at 3am Wednesday. For fun, here are a couple more Kwaj photos

And, real time webcam can be seen at http://countdown.ksc.nasa.gov/elv

What's up June 11

Mon, 11 Jun 2012 14:28:57 -0700

Today we held our L-2 press briefing by phone - the launch is generating a lot of interest.

At 1pm Pacific the Launch Readiness Review was successfully completed. Everyone signed off, and we are good for launch. Some small weather concern but it seems to be at the 10% level at this point.

Tomorrow will be a crew rest day, so besides a few science telecons the team is sleeping, gearing up for launch Wednesday!

What's up June 10?

Sun, 10 Jun 2012 09:38:19 -0700

At the Mission Ops (UCB)
Today we have the final pre-launch change control board, and a rehearsal for the L-2 press conference.

On Kwaj (note this refers to yesterday's activities). Kwaj is one day ahead:

NuSTAR Status Update
Sunday, June 10
Hello Everyone,

Today was a busy day for the NuSTAR Launch Team, Launch Management Coordination Meeting (LMCM) and Mission Dress Rehearsal (MDR) are now complete. During the LMCM, Orbital covered day of launch coordination and activities to ensure the team is in sync for the operation. During LMCM, S&MA presented the LSP Launch day contingency guidance for the NuSTAR Mission in case of a mishap.

MDR consisted of three simulation runs of the Pegasus mission checklist. During each of these runs, anomalies and green cards were introduced to challenge the team as if it was day of launch. The team responded in an excellent manner to resolve each of the condition.

Major Milestone Schedule dates

All days are CONUS

           6/9      LMCM and Dress Rehearsal - Complete
            6/11    LRR
            6/13    ILC

Thanks,
Garrett