Very nice and complete overview article (even though perhaps a bit too much biased towards flare science)!
I've corrected directly some minor typos. Below a list of comments and suggestions the authors may want to consider in an update:
. List of instruments lists LMSAL in column 3; in the case of non-US institutions the table lists countried (UK or Japan); suggest this to be homogenized . why not a proper reference for the proceedings of the 10th anniversary workshop proceedings?
"... no later than December 2008." That has passed. Has it been launched?
- SOHO: is treated relatively briefly, in particular considering the impact that mission had on solar and heliospheric science over the last thirteen years.
- Coronas Photon: again, December 2008 has passed.
- Solar Probe Plus: written perhaps a bit too much in a "sales pitch" style
- Solar Sentinels: are these still in the NASA plan? do they have a budget? Do they still have a nominal launch date in 2016?
The Solar Satellites review by Dennis and Milligan is a very thorough and well-written summary of spacecraft launched to study the Sun. It should be useful to readers attempting to gain an overview of what has been done in experimental solar physics from space. I have two specific comments:
1 - I found only one serious oversight: the omission of the US Department of Defense P78-1 spacecraft that was launched in 1979. The solar instruments are described in Solar Physics, 86, 9 (1983). The first halo coronal mass ejection was discovered by P78-1, as well as the association of mass ejections with interplanetary shocks. Many other CME results were obtained from P78-1. In addition, this satellite obtained very high quality and high spectral resolution X-ray spectra of flares and active regions at wavelengths below about 25 A. The signature of chromospheric evaporation on X-ray line profiles was first reported by P78-1 researchers.
2 - The authors note that the Masuda event hard X-ray loop-top source was “perhaps the most noteworthy scientific result…” from Yohkoh. I personally disagree. The spectacular images from the Soft X-ray Telescope on Yohkoh have provided a huge number of new and exciting results concerning the Sun’s corona. It is very difficult to decide what the most important result from a spacecraft experiment might be when the spacecraft is very productive, as was the case with Yohkoh. And in Table 4, I would list the Institution for SXT as US to be consistent with the other instruments.
Table 1 lists spacecraft. The Helios spacecraft were built by Germany, and both SOHO and Ulysses are ESA spacecraft. The missions are collaborative projects with NASA, but the spacecraft are certainly not NASA spacecraft. I've corrected these in Table 1.
"Sentinels is the NASA component of the joint NASA–ESA Heliophysical Explorers (HELEX) mission that also includes ESA’s Solar Orbiter."
My understanding is that the HELEX program (which was the basis of the Solar Orbiter instrument AO) is "dead". Solar Orbiter is not discussed anymore in the context of flying with the Sentinels but with Solar Probe+. From the website of the 3rd Solar Orbiter Workshop: http://solarorbiter3.oato.inaf.it/
"The aim of the conference is to highlight the uniqueness of the scientific objectives of the Solar Orbiter mission, selected for the ESA Horizon 2000 plus Programme, in the scenario of the new and future missions foreseen for solar physics investigations and in particular in connection with the NASA Solar Probe mission."
and from the program:
14:30 NASA’s heliophysics programme – Science and missions Dick Fisher 15:00 NASA’s Solar Probe Plus – Science goals and status Lika Guhathakurta 15:20 Synergies between Solar Probe Plus and Solar Orbiter Dave McComas 15:40 Orbit synchronization enabling two-point in-situ measurements from Probe and Orbiter Adam Szabo
No word from Sentinels.
I would recommend that the authors check with NASA HQ about the status of Solar Sentinels and update the article accordingly.
Otherwise very nice overview!