About · Sources & methods
Sources and methods
Every number on Mars Progress comes from a dated source or from our Mars engine, which uses NASA’s Mars24 method and JPL’s published orbital elements. This page lists what we rely on and how each live number is made.
Updated Sources (7)
Where facts come from
- Primary sources first: the agency or company itself, such as NASA, ESA, JAXA, CNSA, the UAE Space Agency, SpaceX and Blue Origin.
- Secondary sources are labeled as such. We mostly use Reuters, AP, SpaceNews, Spaceflight Now, NASASpaceflight and Space.com, and other established outlets, when an agency hasn’t said something itself. Wikipedia can point us to a fact; it’s never the only source.
- Every record carries the date it was last checked. Anything not yet checked against a source stays off the site.
- Reports aren’t facts. When a date or plan comes from a news report, the page says who reported it and that the company hasn’t confirmed it.
How the live numbers work
- Mars time and solsNASA’s Mars24 algorithm (Allison and McEwen, 2000). Each rover’s day count uses the local time at its landing site.[1]
- DistancesEarth’s and Mars’s positions from JPL’s approximate orbital elements. Checked against JPL’s Horizons system for 2026–2028, our distance stays within about 0.02%.[2][3]
- Radio delayThe distance divided by the speed of light, 299,792.458 km/s. An AUAn astronomical unit (AU) is the average distance between Earth and the Sun: about 149.6 million km (93 million mi).More in the glossary is 149,597,870.7 km.[6][7]
- Seasons and Mars yearsFrom Mars’s position around the Sun, its Season (Ls)Ls is Mars’s position around the Sun in degrees — 0° starts northern spring, 90° summer, 180° autumn and 270° winter — so it tells you the season.More in the glossary, with years numbered from Mars Year 1, which began on Apr 11, 1955.[1][5]
Each page is built with these values already filled in, so it reads correctly before any script runs. Your browser then keeps them ticking.
How we write dates
Only as precisely as the source. An exact launch time gets a countdown. A known day reads “in 18 days”. A month reads “November 2026”, and a vague target reads “late 2028”. We never show a date nobody has announced.
Times are in UTC, and the page converts them to your time zone.
Units
Kilometers first with miles alongside, °C with °F, and kilograms with pounds. Live numbers and stored facts are converted by code. In the text, we convert from the source’s metric figure and round to match. When a source gives both units itself, we show its figures.
How we judge progress
The six steps in “How close are we to Mars?” move only on announced facts. A step is done when it has happened, and next when a mission for it is flying or has an official date. It’s planned when a company or agency has named a target. When nobody has, it reads no date yet. A target that comes from a news report is labeled as reported.
Questions
Why do your numbers differ slightly from NASA’s?
Rounding and timing. Our live values update every second, while published figures are snapshots. Our Earth–Mars distance stays within about 0.02% of JPL’s Horizons system.
How often is the data checked?
At least once a week, and the same day for launches, landings and mission news. Each record shows the date it was last checked.
Can I use your numbers?
Yes, with a link back. Please name Mars Progress and link to the page you used.
Sources
- NASA GISS — Mars24 Sunclock — algorithm and worked examplesPrimary · checked Oct 2, 2026
- NASA JPL Solar System Dynamics — Approximate Positions of the PlanetsPrimary · checked Oct 2, 2026
- NASA JPL Solar System Dynamics — Horizons SystemPrimary · checked Oct 2, 2026
- NASA NSSDCA — Mars Fact SheetPrimary · checked Oct 2, 2026
- NASA Planetary Data System — start_mars_year (data dictionary)Primary · checked Oct 2, 2026
- International Astronomical Union — IAU resolutions (2012 Resolution B2: the astronomical unit)Primary · checked Oct 2, 2026
- NASA JPL Solar System Dynamics — Astrodynamic ParametersPrimary · checked Oct 4, 2026