Category Archives: Solar Science

Solar Science

The sun goes nearly spotless

The sun seems to be taking a nap: Spaceweather.com – July.16.14

WHERE DID ALL THE SUNSPOTS GO? This week, solar activity has sharply declined. There are only two numbered sunpots on the Earth-facing side of the sun, and each is so small you might have trouble finding them. Click to enlarge this July 17th image from NASA’s Solar Dynamics Observatory and see if you can locate AR2113 and AR2114:

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In case you couldn’t find them, here they are.

Long-time readers absorbing this image might be reminded of 2008-2009, years when the sun plunged into the deepest solar minimum in a century. The resemblance, however, is only superficial. Researchers believe that, underneath the visible surface of the sun, the solar dynamo is still churning out knots of magnetism that will soon bob to the surface to make sunspots. Solar Max is not finished.

For the moment, though, it seems to have paused. Solar activity is very low, and NOAA forecasters put the daily odds of an X-class flare no more than 1%. Updates on Twitter @spaceweatherman.

Keep an eye on the sun via the HobbySpace  Sun & Space Weather page.

DIY space, Solar Science, Space Systems

ISEE-3 Reboot Project: Update on thruster debugging with crowd-sourced expertise

I posted earlier that the reports that the ISEE-3 Reboot Project had given up on restarting the propulsion system were premature. Project member Dennis Wingo gives a detailed account of the crowd-sourced investigation into what is going on with the thrusters and into possible solutions to the failure to get substantial thrust from them: We Are Borg: Crowdsourced ISEE-3 Engineering and the Collective Mind of the Internet – Space College

Corrective Action

There is a pretty good possibility now that we have pressure and or fuel in the tanks but that it is not getting to the propellant lines and out the thrusters. We are going to of course turn the +28 volts on this time! We will also open both valves on one of the fuel systems, the primary and redundant. We will also heat the tanks to see if we can see a rapid increase in temperature. If we see a rapid rise, that would indicate no fuel in the tanks (testing for all eventualities). There are several things we will do to test out and try propulsion to bleed all the gas out of the lines.

What we could see would be not much activity and then toward the end of the pulses from the thrusters we could see propellant flow, temperature increase, and thrust!

Cross your fingers. We will have a pass on July 16th at Arecibo, so we will soon find out what the outcome is.

DIY space, Solar Science, Space Systems

ISEE-3 Reboot Project investigating possible solution to propulsion failure

The ISEE-3 Reboot Project (see posts here, here, and here) appeared to suffer a serious and irreversible setback this week when they were unable to fire the propulsion system to change the spacecraft’s trajectory. While hydrazine fuel still remained in the tank, there did not appear to be any nitrogen to push the fuel into the engine : Curtain Falls on ISEE-3 Reboot Project as Propulsion System Fails – SpaceNews.com.

Now there is some hope that the nitrogen has not leaked out but has dissolved into the hydrazine. The group is asking for help from anyone who might know how to deal with this:

The team asks:

 Did the Nitrogen pressurizing gas dissolve in the Hydrazine in the tanks?

This is something that we would like to research and for efficiencies sake and to get the job done quicker, we would like our project fans out there to help us in this research. I am reading an old USAF document on this now and it may be nothing, but it also may be something. We need to research the following:

– What is the solubility of Nitrogen in Hydrazine?
– What is the temperature dependence?
– Most important, what is the time required to dissolve 1 kg of Nitrogen in 15 kg of Hydrazine? This is an approximation for both tank systems of course.

This is important. Don’t just throw stuff on the wall, help us research this.

Solar Science

Sunspot cycle update

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Bob Zimmerman gives the latest update on the suns activities: The sun continues its ramp down – Behind The Black

ISES Solar Cycle Sunspot Number Progression - NOAA

 

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Bookmark the HobbySpace Sun and Space Weather page and check daily on what’s happening with our nearest star.

DIY space, Solar Science, Space Radio

ISEE-3 engines fired successfully

Congratulations to the ISEE-3 Reboot Project team on successfully firing the thrusters of the 36 year old International Cometary Explorer to spin it back up:

From Wednesday:

Today we fired the A and B thrusters on ISEE-3 to perform a spin-up burn. Preliminary results confirm the burn and a change in rotation. Spin rate was originally 19.16 rpm. It is now at 19.76 rpm. The original mission specifications call for 19.75 +/- 0.2 rpm- so we are exactly where we wanted to be.

We are now collecting telemetry in advance of our next DSN pass and our ATP-3 review with NASA. The earliest we expect to make our Trajectory Correction Maneuver is next week.

All in all, a very good day.

See previous posts here and here.