Savitar is one of the name of hindu diety 'Surya'(sun).The mantra as every vedic mantras do explains science like Electromagnetic induction etc.The science in this mantra is that the sun holds the earth and all planents continuosly and rotates which is known as revolution with the perfection.Savitar or sun fixed it's axis to all the planents like a rope tied to horse and savitor looks for perfect revolution of all the planets with exactly same distance from planets even though revolving or rotating.The centre of our solar system is sometimes exactly at the sun and sometime just a distance nearby.So here earth is fixed but in accordance with sun.
Do Vedas say Earth is static?
Lets see some Vedic quotes which says earth is static.
Oh Man ! He who made the trembling earth static is Indra. (Rig Ved 2/12/12)
The God who made the earth stable (Yajur Ved 32/6)
Indra protects the wide earth which is immovable and has many forms (Atarv Ved 12/1/11)
Let us walk on the Wide and Static earth (Atharv Ved 12/1/17)
Even sanskrit scholars are not able to correctly read it how can translate correctly to english.
One suggestion :- read puranas first as one who knows whats written in veda understands it and one who do so becomes epic like ravana and many others.To understand veda don't read any vedas just read puranas and create your yoga techniques which relaxes u as very few saints know this others don't.Meditate and meditate u will ultimately understand vedas like vishwamitra.If vedas was such easy to understand than why only very rare ones are titled as veda knower.Instead meditate on universe if u so u will ultimately be a veda knower