MTOF Proton Monitor

There is a problem with the motor controlling the High Gain Antenna on the SOHO spacecraft. Science data coverage may be less than complete for 1-2 weeks every 90 days (when the spacecraft gets 'flipped'). The next "keyhole" period can be found in this table.

Most Recent Shock Candidates:

Dates

05 Dec 2025

12 Nov 2025

11 Nov 2025

1609

1855

2344

day of year

339

316

315

F/R

REV

fwd

Zone

Confidence Level

25%

98%

99%

Current time in UTC

Two Day PM Plot — Data ending at 1105 GMT on December 07, 2025 (2 minute ascii data)

Two Week PM Plot — Data ending at 2355 GMT on December 06, 2025 (15 minute ascii data)

Where is SoHO?

The predicted position of the SOHO spacecraft in the GSE coordinate system (X,Y,Z) in Earth radii at 0610 GMT on Oct 15, 2020:

( 193, 32, 14 )

Daily Orbit Data:

Launch through 1996, 1997, 1998, 1999, 2000, 2001, 2002, 2003, 2004, 2005, 2006, 2007, 2008, 2009, 2010, 2011, 2012, 2013, 2014, 2015, 2016, 2017, 2018, 2019, 2020, 2021, 2022, 2023, 2024, 2025

What's being plotted?

What do the colors mean?

About the PM sensor

The SOHO mission

The Proton Monitor (PM) is one of the scientific sensors in the Charge, Element, and Isotope Analysis System (CELIAS) instrument package aboard the SOHO spacecraft.

LIVE from College Park...

the latest 48 hours of solar wind data

brought to you by the CELIAS/MTOF Proton Monitor on the SOHO Spacecraft

ISSI video: 25 Years of SOHO and First Glimpses of Parker Solar Probe and Solar Orbiter

Where is SoHO?