Short answer: NASA does not study astrology and has stated plainly that it is not a science. Its well-known explainer pointed out two astronomical facts: the Sun passes through 13 constellations, not 12, and the Earth's slow wobble has shifted the sky by roughly 24 degrees since the Western zodiac was fixed. Western (tropical) astrology does not adjust for that shift. Vedic (sidereal) astrology does.
The "13th zodiac sign" story
NASA's educational site explained that the Babylonians, around 3,000 years ago, divided the Sun's path into 12 equal parts and chose 12 constellations, leaving out Ophiuchus, which the Sun also crosses. When this resurfaced online, headlines claimed "NASA changed your zodiac sign." NASA's response was simple: it did not change anything, it was only describing the sky. Astrological signs are 30-degree divisions of the ecliptic, not the uneven constellations themselves.
The real point: precession
The Earth's axis wobbles like a spinning top, completing one circle in about 26,000 years. Because of this, the point where the Sun stands at the spring equinox slides backwards against the stars by about one degree every 72 years. Over two millennia that adds up to around 24 degrees — nearly a whole sign.
Tropical vs sidereal: where Vedic astrology differs
Western astrology uses the tropical zodiac, tied to the seasons, so its signs have drifted away from the stars. Vedic astrology uses the sidereal zodiac, tied to the fixed stars, and subtracts the accumulated drift — called the ayanamsa. VedikPatrika uses the Lahiri ayanamsa, the standard adopted by the Government of India's calendar reform committee.
The practical result: if you were told you are a Leo by a Western app, your sidereal Sun is very likely in Karka (Cancer). And in Vedic practice your rashi is your Moon sign anyway, which can be a completely different sign. Check yours with the sun sign calculator and the rashi (Moon sign) calculator.
So is NASA right that astrology is not science?
On the scientific question, yes: astrology's interpretations have not been validated by controlled experiments, and we say so openly in is astrology 100% true?. But the specific "your sign is wrong" criticism applies to tropical astrology. A sidereal chart is computed against the actual star background, using real astronomical positions.
Why this matters for your chart
Your Vedic chart should be calculated from your exact birth time and place with a sidereal ayanamsa — not borrowed from a Sun-sign column. A free kundli shows your sidereal lagna, Moon sign and nakshatra in seconds, and the rising sign calculator gives you your ascendant on its own.